Edge barrier film for electronic devices

ABSTRACT

In some embodiments, a first product is provided. The first product may include a substrate, a device having a device footprint disposed over the substrate, and a barrier film disposed over the substrate and substantially along a side of the device footprint. The barrier film may comprise a mixture of a polymeric material and non-polymeric material. The barrier film may have a perpendicular length that is less than or equal to 3.0 mm from the side of the device footprint.

BACKGROUND OF THE INVENTION

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices (OLEDs), organic phototransistors, organic photovoltaiccells, and organic photodetectors. For OLEDs, the organic materials mayhave performance advantages over conventional materials. For example,the wavelength at which an organic emissive layer emits light maygenerally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule is tris (2-phenylpyridine)iridium, denoted Ir(ppy)3, which has the structure of Formula I:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

BRIEF SUMMARY OF THE INVENTION

Some embodiments provided herein may comprise products, and methods ofmanufacturing products, that comprise a barrier film (i.e. an edgesealant film or layer) that may decrease the degradation of a device andprotect sensitive components from ingress of environmental contaminantssuch as water vapor (e.g. the barrier film may be utilized in electronicdevices that consist of atmosphere sensitive components, such aselectrodes or organic layers). The barrier film may be used inconjunction with any form of top encapsulation (such as a thin filmencapsulation or glass encapsulation) and may provide an edge seal toincrease the shelf lifetime of the encapsulated device. Moreover, thebarrier film that forms the edge seal may have dimensions that aresmaller than traditional edge sealant layers, thereby reducing the sizeof the border area (dead space) of the product.

In some embodiments, a first product is provided. The first product mayinclude a substrate, a device having a device footprint disposed overthe substrate, and a barrier film disposed over the substrate andsubstantially along a side of the device footprint. The barrier film maycomprise a mixture of a polymeric material and non-polymeric material.The barrier film may have a perpendicular length that is less than orequal to 3.0 mm from the side of the device footprint.

In some embodiments, in the first product as described above, the devicefootprint may comprise an active device area and an inactive devicearea. In some embodiments, the barrier film may have a perpendicularlength that is less than or equal to 3.0 mm from the side of theinactive device area. In some embodiments, the barrier film may notextend to a distance of greater than 3.0 mm from a side of the activedevice area.

In some embodiments, in the first product as described above, the devicefootprint may comprise an active device area, and the barrier film mayhave a perpendicular length that is less than or equal to 3.0 mm fromthe side of the active device area.

In some embodiments, in the first product as described above, thebarrier film may comprise a mixture of a polymeric silicon and inorganicsilicon. In some embodiments, the mixture of polymeric silicon andinorganic silicon is substantially uniform across the layer.

In some embodiments, in the first product as described above, thebarrier film may have a perpendicular length that is less than or equalto 2.0 mm from the side of the device footprint. In some embodiments,the barrier film may have a perpendicular length that is less than orequal to 1.0 mm from the side of the device footprint.

In some embodiments, in the first product as described above, thebarrier film may not have a perpendicular length that is greater than3.0 mm from the side of the device footprint. In some embodiments, thebarrier film may not have a perpendicular length that is greater than2.0 mm from the side of the device footprint. In some embodiments, thebarrier film does not have a perpendicular length that is greater than1.0 mm from the side of the device footprint.

In some embodiments, in the first product as described above, thebarrier film may not have a perpendicular length that is greater than3.0 mm or less than 1.0 mm from the side of the device footprint. Insome embodiments, the barrier film may not have a perpendicular lengththat is greater than 2.0 mm or less than 0.5 mm from the side of thedevice footprint.

In some embodiments, in the first product as described above, thebarrier film may comprise a substantially uniform material. In someembodiments, the barrier film may comprise a uniform material.

In some embodiments, in the first product as described above, thebarrier film may comprise a mixture of an oxide and polymeric silicone.In some embodiments, the barrier film may comprise at least 40%inorganic silicon. In some embodiments, the barrier film may comprise atleast 60% inorganic silicon. In some embodiments, the barrier film maycomprise at least 80% inorganic silicon.

In some embodiments, in the first product as described above, a surfaceof the barrier film may be disposed adjacent to a surface of thesubstrate to form a first interface, and the ratio of the index ofrefraction of the bulk of the barrier film and the index of refractionof a portion of the barrier film that is within 10 nm of the interfaceis between 0.9993 and 0.9247.

In some embodiments, in the first product as described above, where asurface of the barrier film is disposed adjacent to a surface of thesubstrate to form a first interface, the index of refraction of aportion of the barrier film that is within 10 nm of the interface may bebetween 1.35 and 1.459.

In some embodiments, in the first product as described above, where asurface of the barrier film is disposed adjacent to a surface of thesubstrate to form a first interface, the barrier film may comprise amaterial having a bulk diffusion coefficient of water vapor of less than10⁻¹³ cm²/sec. In some embodiments, the diffusion coefficient of watervapor at the first interface may be between 10⁻⁸ cm²/sec and 10⁻¹³cm²/sec when exposed to an ambient temperate of 65° C. and relativehumidity of 85%.

In some embodiments, in the first product as described above, where asurface of the barrier film is disposed adjacent to a surface of thesubstrate to form a first interface, the barrier film may comprise amaterial having a bulk diffusion coefficient of water vapor. The ratioof the bulk diffusion coefficient of water vapor of the barrier film anda diffusion coefficient of water vapor near the first interface may bebetween 1 and 10⁻⁵. In some embodiments, the ratio of the bulk diffusioncoefficient of water vapor of the barrier film and a diffusioncoefficient of water vapor within 10 nm of the first interface may bebetween 1 and 10⁻⁵.

In some embodiments, in the first product as described above, the devicemay further comprise a conductive layer disposed over the active devicearea. In some embodiments, a portion of the barrier film may be disposedat least partially over the conductive layer. In some embodiments, aportion of the barrier film may be disposed over the entire conductivelayer.

In some embodiments, in the first product as described above where thedevice comprises a conductive layer disposed over the active devicearea, a top sealant layer may be disposed over the conductive layer. Thetop sealant layer and the barrier film may comprise different materials.

In some embodiments, in the first product as described above, the firstproduct may comprise a border area (i.e. dead space). The border areamay have a thickness that is less than 3.0 mm.

In some embodiments, in the first product as described above, where thefirst product comprises a border area, the border area may have athickness that is less than 2.0 mm. In some embodiments, the border areamay have a thickness that is less than 1.0 mm.

In some embodiments, the first product as described above may comprise aconsumer device. In some embodiments, the first product may compriseanyone of: a solar cell, a thin film battery, an organic electronicdevice, a lighting panel or a lighting source having a lighting panel, adisplay or an electronic device having a display, a mobile phone, anotebook computer, a tablet computer, or a television.

In some embodiments, in the first product as described above, the devicemay comprise an organic layer. In some embodiments, the organic layermay comprise an electro-luminescent material. In some embodiments, thedevice may comprise an OLED.

In some embodiments, a first method may be provided. The first methodmay comprise the steps of providing a substrate having a device having adevice footprint disposed over the substrate, and fabricating a barrierfilm over the substrate and substantially along a side of the devicefootprint, where the barrier film may be fabricated so as to have aperpendicular length that is less than or equal to 3.0 mm from the sideof the device footprint.

In some embodiments, in the first method as described above, the devicefootprint may comprise an organic layer. In some embodiments, theorganic layer may comprise an electroluminescent (EL) material. In someembodiments, the device may comprise an OLED.

In some embodiments, in the first method as described above, the barrierfilm may be fabricated so as to have a perpendicular length that is lessthan or equal to 2.0 mm from the side of the device footprint. In someembodiments, the barrier film may be fabricated so as to have aperpendicular length that is less than or equal to 1.0 mm from the sideof the device footprint.

In some embodiments, in the first method as described above, the step offabricating the barrier film may comprise chemical vapor deposition. Insome embodiments, the step of fabricating the barrier film may utilizean organosilicon precursor.

In some embodiments, in the first method as decried above, the step offabricating the barrier film so as to have a perpendicular length thatis less than or equal to 3.0 mm from the side of the device footprintmay comprise depositing the barrier film through a mask such that theperpendicular length is less than or equal to 3.0 mm from the side ofthe device footprint.

In some embodiments, in the first method as described above, the step offabricating the barrier film so as to have a perpendicular length thatis less than or equal to 3.0 mm from the side of the device footprintmay comprise the steps of: depositing a barrier film over the substrateand substantially along a side of the device footprint, wherein thebarrier film is deposited so as to have a perpendicular length that isgreater than or equal to 3.0 mm from the side of the device footprint,and, after depositing the barrier film, breaking the barrier film suchthat the barrier film has a perpendicular length that is less than orequal to 3.0 mm from the side of the device footprint. In someembodiments, the step of breaking the barrier film may be accomplishedby, or in combination with, breaking the substrate.

In some embodiments, a first product prepared by a process may beprovided. The process for preparing the first product may comprise thesteps of providing a substrate having a device disposed over thesubstrate, where the device has a device footprint, and fabricating abarrier film over the substrate and substantially along a side of thedevice footprint, where the barrier film may be fabricated so as to havea perpendicular length that is less than or equal to 3.0 mm from theside of the device footprint.

In some embodiments, in the first product prepared by a process asdescribed above, the device may comprise an organic layer. In someembodiments, the organic layer may comprise an organicelectroluminescent (EL) material. In some embodiments, the device maycomprise an OLED.

In some embodiments, in the first product prepared by a process asdescribed above, the barrier film may be fabricated so as to haveperpendicular length that is less than or equal to 2.0 mm from the sideof the device footprint. In some embodiments, the barrier film isfabricated so as to have perpendicular length that is less than or equalto 1.0 mm from the side of the device footprint.

In some embodiments, in the first product prepared by a process asdescribed above, the step of fabricating the barrier film may comprisesdepositing the first barrier film using an organosilicon precursor. Insome embodiments, the step of fabricating the barrier film may comprisechemical vapor deposition. In some embodiments, the step of fabricatingthe barrier film may comprise plasma enhance chemical vapor deposition(PE-CVD). In some embodiments, the barrier film consists essentially ofa mixture of polymeric silicon and inorganic silicon, where the weightratio of polymeric silicon to inorganic silicon is in the range of 95:5to 5:95, and where the polymeric silicon and the inorganic silicon arecreated from the same precursor material. In some embodiments, at leastan 0.1 μm thickness of the barrier film is deposited under the samereaction conditions for all the reaction conditions in the depositionprocess and the water vapor transmission rate is less than 10⁻⁶ g/m²/daythrough the at least 0.1 μm thickness of the barrier film.

In some embodiments, in the first product prepared by a process asdescribed above, where the step of fabricating the barrier filmcomprises depositing the first barrier film using an organosiliconprecursor, the precursor material may comprise hexamethyl disiloxane ordimethyl siloxane. In some embodiments, the precursor material maycomprise a single organosilicon compound. In some embodiments, theprecursor material may comprise a mixture of organosilicon compounds.

In some embodiments, in the first product prepared by a process asdescribed above, the step of fabricating the barrier film may comprisedepositing the barrier film through a mask such that the perpendicularlength is less than or equal to 3.0 mm from the side of the devicefootprint. In some embodiments, the perpendicular length may be lessthan or equal to 1.0 mm from the side of the device footprint.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows a cross-section of an exemplary device having a multilayerbarrier. The footprints of the deposition masks used for both inorganicand polymer films may be the same, which is larger than the devicefootprint by, for example, 1.0 mm in this exemplary device.

FIG. 4 shows a cross-section of an exemplary device having a multilayerbarrier. The footprint of the mask used for the polymer film may belarger than the device footprint by, for example, 1.0 mm, and thefootprint of the mask of the inorganic film may be larger than that ofthe polymer film by, for example, 1.0 mm.

FIG. 5 shows a cross-section of an exemplary device having a multilayerbarrier. The footprints of the masks used for each stack of inorganicand polymer film may be larger than the previous stack by, for example,1.0 mm. The footprint of the first stack is larger than that of thedevice footprint of the device by, for example, 1.0 mm.

FIG. 6 shows a cross-section of a barrier film as an edge sealant for anexemplary device in accordance with some embodiments. The difference inthe footprint of the mask used for the barrier film as the edge seal ofthis exemplary device and the device footprint is shown as (“l”).

FIG. 7 shows a cross-section of an exemplary device having a barrierfilm as an edge sealant and also as the top encapsulation, in accordancewith some embodiments.

FIG. 8 comprises photographs of the luminescent areas of a 2.0 mm²bottom emitting OLED test pixel coated with a 9.0 μm thick barrier filmas a top encapsulation layer, in accordance with some embodiments. Thefootprint of the barrier film as the edge sealant and top encapsulationin this exemplary device was at least 2.0 mm larger than the footprintof the polymer material used in the OLED.

FIGS. 9(a) and 9(b) show experimental results for two tests conducted bythe inventors.

FIG. 9(a) comprises photographs of the luminescent areas of threeexemplary 1 cm² bottom emitting OLED test pixels coated with a 9.0 μmthick barrier film as the top encapsulation. The photographs were takenat the start of testing and after periods of accelerated storage atenvironmental conditions of 65° C. and 85% relative humidity (RH). Thefootprint of the barrier film as the edge sealant (i.e. theperpendicular length from the side of the device footprint) for each ofthe devices was (a) 1.0 mm, (b) 2.0 mm, and (c) 3.0 mm larger than thedevice footprint that comprises the organic material used in theexemplary OLED.

FIG. 9(b) comprises photographs of three exemplary 4.0 mm² calcium (Ca)buttons coated with a 9.0 μm thick barrier film as the topencapsulation. The photographs were taken during the periods ofaccelerated storage at environmental conditions of 85° C. and 85% RH.The footprint of the barrier film as the edge sealant (i.e. theperpendicular length from Ca button) for each of the devices was (a) 1.0mm, (b) 2.0 mm, and (c) 3.0 mm larger than the footprint of Ca button.

FIG. 10 shows a cross-section of an exemplary device in which thebarrier film is used as the edge sealant and the top encapsulation, inaccordance with some embodiments.

FIG. 11 shows a cross-section of an exemplary device in which thebarrier film is used as an edge sealant, but is not used as the topencapsulation in accordance with some embodiments. The top encapsulationin this exemplary device comprises a single layer barrier film. Thefootprints of the mask used for the top encapsulation film in thisexemplary embodiment may be approximately the same size as that used forthe device footprint. The footprint of the mask used to deposit thebarrier film as the edge sealant may be, for example, 1.0 mm larger thanthat of the device footprint.

FIG. 12 shows a cross-section of an exemplary device in which thebarrier film is an edge sealant, but it does not comprise the topencapsulation in accordance with some embodiments. The top encapsulationin this exemplary device is a multilayer barrier film. In this example,the footprint of the mask used for the top encapsulation may be the samesize as that used for the device footprint. The footprint of the maskused to deposit the barrier film as the edge sealant may be, forexample, 1.0 mm larger (or any suitable value) than that of the devicefootprint.

FIG. 13 shows a cross-section of an exemplary device in which thebarrier film is an edge sealant, but it is not the top encapsulation inaccordance with some embodiments. The top encapsulation in this examplecomprises a glass encapsulation using epoxy. The footprint of the maskused for the top encapsulation in this example may be the same size asthat used for the device footprint. The footprint of the mask used todeposit the barrier film as the edge sealant may be 1.0 mm larger (orany suitable value) than that of the device footprint.

FIG. 14 shows a cross-section of an exemplary device in which thebarrier film is an edge sealant and where the top encapsulationcomprises a glass encapsulation using epoxy, in accordance with someembodiments. In this example, the epoxy is not deposited directly on thedevice (e.g. on one or more layers of the device such as a conductivelayer), but a layer of barrier film is disposed between the epoxy andthe device (or the one or more layers of the device).

FIG. 15 shows a top-view of an exemplary product in accordance with someembodiments.

FIG. 16 shows a cross-sectional view of the exemplary product shown inFIG. 15 in accordance with some embodiments.

FIG. 17 shows a cross-sectional view of the exemplary product shown inFIG. 15 in accordance with some embodiments.

DETAILED DESCRIPTION OF THE INVENTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, and a cathode 160. Cathode 160 is acompound cathode having a first conductive layer 162 and a secondconductive layer 164. Device 100 may be fabricated by depositing thelayers described, in order. The properties and functions of thesevarious layers, as well as example materials, are described in moredetail in U.S. Pat. No. 7,279,704 at cols. 6-10, which are incorporatedby reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F.sub.4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. patent application Ser. No. 10/233,470, which is incorporated byreference in its entirety. Other suitable deposition methods includespin coating and other solution based processes. Solution basedprocesses are preferably carried out in nitrogen or an inert atmosphere.For the other layers, preferred methods include thermal evaporation.Preferred patterning methods include deposition through a mask, coldwelding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819,which are incorporated by reference in their entireties, and patterningassociated with some of the deposition methods such as ink jet and OVJP.Other methods may also be used. The materials to be deposited may bemodified to make them compatible with a particular deposition method.For example, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processibility than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the invention maybe incorporated into a wide variety of consumer products, including flatpanel displays, computer monitors, televisions, billboards, lights forinterior or exterior illumination and/or signaling, heads up displays,fully transparent displays, flexible displays, laser printers,telephones, cell phones, personal digital assistants (PDAs), laptopcomputers, digital cameras, camcorders, viewfinders, micro-displays,vehicles, a large area wall, theater or stadium screen, lightingfixtures, or a sign. Various control mechanisms may be used to controldevices fabricated in accordance with the present invention, includingpassive matrix and active matrix. Many of the devices are intended foruse in a temperature range comfortable to humans, such as 18 degrees C.to 30 degrees C., and more preferably at room temperature (20-25 degreesC.).

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The terms halo, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, arylkyl,heterocyclic group, aryl, aromatic group, and heteroaryl are known tothe art, and are defined in U.S. Pat. No. 7,279,704 at cols. 31-32,which are incorporated herein by reference.

As used herein, the “active device area” of a device may refer to theportion of the device in which electrons, holes, and/or photons aregenerated or absorbed and may comprise one or more organic and/orsemi-conductor materials (such as organic semi-conductors or dopedsilicon). For organic electronic devices, the active device area maycomprise one or more organic layers. For example, the active device areaof an OLED may refer to the emissive area of the device (i.e. theportion of the device that emits light) and may include an organicelectro-luminescent material. The active device area of a solar cell mayrefer to the portion of the device where photons are absorbed andelectrons are released (e.g. it may refer to the portion of the devicethat comprises a semi-conductor material). For a thin film battery, theactive device area may refer to the electrolyte and may comprise, forexample, lithium phosphorus oxynitride. These are just a few examples ofactive device areas of exemplary devices, and it should be appreciatedthat embodiments disclosed herein are not so limited.

As used herein, a “barrier film” or “barrier layer” may refer to a layerof material that may be utilized to decrease the permeation of gases,vapors, and/or moisture (or other environmental particulates) into theactive device area of the device so as to increase lifetime and/orreduce performance degradation. In some embodiments, the barrier filmmay comprise a hybrid layer comprising a mixture of a polymeric materialand a non-polymeric material. As used herein, the term “non-polymeric”refers to a material made of molecules having a well-defined chemicalformula with a single, well-defined molecular weight. A “nonpolymeric”molecule can have a significantly large molecular weight. In somecircumstances, a non-polymeric molecule may include repeat units. Asused herein, the term “polymeric” refers to a material made of moleculesthat have repeating subunits that are covalently linked, and that has amolecular weight that may vary from molecule to molecule because thepolymerizing reaction may result in different numbers of repeat unitsfor each molecule. For example, in some embodiments, the barrier filmmay comprise a mixture of polymeric silicon and inorganic silicon.Examples of barrier films are described in more detail below.

As used herein, the “border area” (i.e. dead space) of the device maycomprise the combination of the “inactive device area” and the“non-device edge area.” As used in this context, the “thickness” of theborder area may refer to the distance from the device footprint to theedge of the border area (which may also comprise the edge of thesubstrate in some embodiments) in a direction that is perpendicular to aside of the device footprint.

As used herein, the term “comprising” is not intended to be limiting,but may be a transitional term synonymous with “including,”“containing,” or “characterized by.” The term “comprising” may therebybe inclusive or open-ended and does not exclude additional, unrecitedelements or method steps when used in a claim. For instance, indescribing a method, “comprising” indicates that the claim is open-endedand allows for additional steps. In describing a device, “comprising”may mean that a named element(s) may be essential for an embodiment, butother elements may be added and still form a construct within the scopeof a claim. In contrast, the transitional phrase “consisting of”excludes any element, step, or ingredient not specified in a claim. Thisis consistent with the use of the term throughout the specification.

As used herein, the “inactive device area” of a device may refer toportions of the device that comprises one or more layers of materials(such as organic layers) that are also included in the active area, butwhich does not comprise a part of the device where electrons, holes,and/or photons are generated or absorbed (i.e. it is not a part of theactive device area of the device). For example, with regard to an OLED,the inactive device area may include one or more organic layers and/or aportion of an electrode, but this portion of the device may not includeone or more of the other organic layers (or one or more electrodes) andtherefore does not emit light. The inactive device area is often, butnot always, the result of depositing an organic layer so as to extendbeyond the edges of one of the electrodes to prevent or reduce thelikelihood of shorting. In some instances, an insulating layer (e.g.“grid layer”) may be disposed over the substrate and a portion of anelectrode so as to electrically insulate the conductive layers of thedevice (see, e.g., FIGS. 15-17). These areas generally do not emit lightand therefore would comprise a portion of the “inactive device area.” Inmost instances, the inactive device area of the device is disposedadjacent to one or more sides of the active device area.

As used herein, the “device footprint” may refer to the total area ofthe “active device area” of the device and the “inactive device area” ofthe device. With reference to an organic device for illustrationpurposes, the device footprint may refer to the portion of the device inwhich one or more organic layers (i.e. the organic footprint) and/or oneor more insulating grid layers are disposed over the substrate.

As used herein, a “non-device edge area” may refer to the area aroundthe device footprint—that is, the portion of a product that does notinclude the “active device area” or the “inactive device area” of thedevice. For example, the non-device edge area may not comprise one ormore of the layers that of the active device area of the device. Withreference to organic electronic devices, the non-device edge area mayrefer to the portion of product that typically does not comprise anorganic layer or an insulating layer (such as a grid layer that isdisposed over one of the electrodes of the OLED). For instance, thenon-device edge area may refer to the non-emitting areas of the OLEDthat do not comprise a part of the inactive device area. The non-deviceedge area may include the portions of the prodict in which one or morebarrier films or layers are disposed along a side of the devicefootprint.

As used herein, the “perpendicular length” of the barrier film may referto the distance from a portion of the barrier film that is disposedclosest to the device footprint (e.g. adjacent to the active device areaor inactive device area) to another portion of the barrier film that isdisposed farthest away from the device footprint (e.g. an edge of thebarrier film) in a direction that is perpendicular to the side of thedevice footprint and parallel to the surface of the substrate that thebarrier film is disposed over. In other words, the perpendicular lengthmay be a measure of the distance that the barrier film extends away fromthe device footprint (i.e. the footprint of the barrier film beyond thedevice footprint). The reason for utilizing the “side” of the devicefootprint as determining the perpendicular length is to generallyexclude the corner effects, where the length of the barrier film mayvary because of the shape of the device footprint. Thus, in general, theperpendicular length may correspond to the length of the barrier filmdisposed so as to provide resistance to the horizontal ingress ofmoisture (and other contaminants) into the active device area. In someembodiments, the perpendicular length may also correspond to the lengthof the barrier film adjacent to the substrate; however, embodiments arenot limited such as when one or more conductive layers may extend beyondthe device footprint (e.g. to make electrical connections), examples ofwhich are illustrated in FIGS. 15 and 16 and described below.

It should be noted that although embodiments described below may makereference to organic devices such as OLEDs, embodiments are not solimited. The inventors have found that barrier films comprising amixture of a polymeric material and a non-polymeric material as an edgesealant may be generally used in any thin film electronic device,particularly those that may have a component (or components) that issensitive to environmental permeants such as water vapor. Moreover, theinventors have found that the exemplary barrier film may be used as anedge sealant having a perpendicular length (as described above) that isless than 3.0 mm (preferably less than 2.0 mm; and more preferably lessthan 1.0 mm) while still providing adequate device performance andlifetime. This reduction in the size of the edge sealant may reduce thesize of the non-active edge areas of such devices and therebypotentially reduce the border area and/or the overall size of a product(such as an electronic device) that comprises the exemplary barrier filmas an edge sealant.

In general, electronic devices having moisture sensitive electroniccomponents (such as water vapor sensitive electrodes) may degrade uponstorage because of the atmospheric conditions. The degradation may be inthe form of dark spots caused by the ingress of water vapor and oxygenvertically through the bulk of a thin film encapsulation (TFE) (orthrough particles embedded in the TFE), or by the ingress of water vaporand oxygen horizontally through the edge of the TFE. The TFE may also bereferred to herein as a barrier layer or barrier film. The edge ingressof the water vapor typically occurs either via the horizontal permeationof the permeants (e.g. water vapor molecules) through the TFE itself(see, e.g., FIG. 6, 604 described below) or via the horizontalpermeation of the permeants through the interface of the TFE with theunderlying substrate (see, e.g., FIG. 6, 605 described below). Theinventors have thereby found that it is preferred that a TFE providingan edge seal for an electronic device reduces both types of horizontalpermeations (i.e. permeation across the layer itself and permeation atthe interface between the layer and the substrate). In this regard,embodiments provided herein comprise an edge seal that may provide forimproved performance and may be used for electronic devices that may besensitive to atmosphere conditions, such as moisture.

Previous edge seals that were widely in use utilized multilayerbarriers. For example, many devices comprised multilayer barriers thatconsisted of alternate layers of inorganic and polymer films. Thesebarriers work on the principle of delaying the permeant molecules fromreaching the device by forming a long and tortuous diffusion path. Someexamples of these multilayer barriers will be described below.

One of the prior methods for encapsulating a device with a multilayerbarrier utilizes the same mask for both the inorganic and the polymerfilms; however, the size of the mask is larger than the footprint of adevice so as to provide some edge ingress barrier (and also to allow formask alignment tolerance). Assuming an alignment tolerance of 500 μm(which is reasonable for most fabrication processes) for both the devicemask (e.g. the mask that may be used to deposit the layers that forththe active device area, inactive device area, and/or other componentssuch as electrodes) and the encapsulation mask (e.g. the mask used todeposit the inorganic and the polymer films), this implies that theencapsulation mask should be about 1.0 mm larger than the device mask soas to prevent any device exposure when both the deposition of the deviceand the alignment of the encapsulation mask is off in the worst casescenario. It may also be assumed that the thickness of the inorganicfilm of the multilayer barrier is about 50 nm, and the thickness of thepolymer film of multilayer barrier is about 800 nm, as is typically thecase for such devices. FIG. 3 provides an example of such a device.

FIG. 3 shows a product 300 that comprises a substrate 310, a device 301having a device footprint (which may include an active device area andan inactive device area) disposed over the substrate 310, and aplurality of inorganic layers 302 and polymer layers 303 thatencapsulate the device 301. The product 300 of FIG. 3 shows a multilayerbarrier encapsulation process consisting of a 5-layer stack thatincludes five inorganic layers (302) with four polymer layers (303)disposed between the organic layers (i.e. sandwiched between). Ingeneral, this type of masking and deposition method may be relativelysimple to fabricate because it uses a minimum number of mask changes(thus adding minimum processing time for fabrication)—i.e. after thedevice 301 and corresponding components are deposited on the substrate,both the inorganic layer and the polymer layer may be deposited througha single mask. As shown in FIG. 3, this exemplary multi-layer barrierprovides a direct path (i.e. Path-1 shown by the arrow 304) for watervapor to travel across the polymer layer 303 horizontally and reach thedevice 301 of product 300 (e.g. an environmentally sensitive electrodeor organic layer) by permeating across just one inorganic layer 302(i.e. the inorganic layer disposed adjacent to the device footprint ofthe device 301). Thus, the edge seal provided by this type of multilayerbarrier as shown in FIG. 3 is mostly dependent on the permeation rate ofwater vapor across the polymer material 303 (which is typically higherthan the permeation rate of the inorganic material). In general, fordevice designs such as those shown in FIG. 3, to achieve suitable deviceperformance and lifetime, such a device would use a footprint for theencapsulation layer (e.g. the polymer 303 and inorganic 302 layers) thatis much larger than the footprint of device 301. That is, the use of asingle mask size for both inorganic 302 and organic 303 films that islarger than the device footprint to deposit the edge seal may not be aworking or practical solution to providing a device with a minimalamount of border area (i.e. dead space). This is further illustrated inthe example provided below.

The value of the diffusion constant of water vapor in polyacrylatepolymer (a commonly used encapsulation material) at 25° C. can becalculated by using the diffusion constant (“D”) of polyacrylate polymerat 38° C. as calculated by G. L. Graff, R. E. Williford, and P. E.Burrows, Mechanisms of vapor permeation through multilayer barrierfilms: Lag time versus equilibrium permeation, J. Appl. Phys., 96 (4),pp. 1840-1849 (2004) (i.e. the diffusion constant (D) at 38° C.˜8.5×10⁻⁹cm²/sec), which is incorporated herein by reference in its entirety, andutilizing the activation energy of water vapor in such a polymer as wascalculated by Z. Chen, Q. Gu, H. Zou, T. Zhao, H. WANG, MolecularDynamics Simulation of Water Diffusion Inside an Amorphous PolyacrylateLatex Film, Journal of Polymer Science: Part B: Polymer Physics, Vol.45, 884-891 (2007) (found to be approximately equal to 13 kJ/mole),which is also incorporated herein by reference in its entirety. In thismanner, the diffusion constant of water vapor in polyacrylate polymer at25° C. can be estimated to be ˜6.8×10⁻⁹ cm²/sec. Using this diffusionconstant, the lag time of water vapor diffusion through Path-1 (304) forthe device 300 shown in FIG. 3 can be estimated. As used in thiscontext, the lag time (t_(l)) refers to the approximate diffusion timeof permeant molecules (e.g. water vapor molecules) across a distance(l), and is related to the diffusion constant of the material by therelation given by: t_(l)=l²/(6D), as shown by Graff et al., Mechanismsof vapor permeation through multilayer barrier films: Lag time versusequilibrium permeation, J. Appl. Phys., 96 (4), pp. 1840-1849 (2004).Using the diffusion constant (D) of water vapor in polyacrylate polymercalculated above, the lag time at 25° C. may be calculated to be closeto 70 hours for a path length of 1.0 mm. That is, for the exemplaryencapsulation method shown in FIG. 3, it would generally take watervapor approximately 70 hours at room temperature to reach the inorganiclayer 302 adjacent to the footprint of device 301 of the product 300when traveling horizontally along Path-1 (304). Once the permeantcrosses the polymer layer 303 along Path-1 (304), it need only permeateacross just a single inorganic film layer 302 (which typically has athickness of approximately 50 nm) to reach the footprint of device 301.The permeants can then reach the active device area quickly throughdefects (e.g. pinholes, cracks, particles, etc.) and cause damage.Needless to say, this design may result in device degradation that isunacceptable for an intended purpose or application.

Another approach using a multilayer barrier to encapsulate the device ofa product is shown in FIG. 4. The product 400 comprises a substrate 410,a device 401 having a device footprint (which may comprise an activedevice area and an inactive device area) disposed on the substrate 410,and a plurality of inorganic layers 402 and polymer layers 403 disposedover the device 401. As shown, the device 400 uses an inorganic layermask (used in depositing the inorganic layers 402) that is larger thanthe polymer layer mask (used in depositing the polymer layers 403) suchthat an inorganic layer 420 covers the side of the polymer layers 403.As shown in FIG. 4, even in this approach, the horizontal ingress path(i.e. Path-1 shown by the arrow 404) is the easiest path for water vaporto travel horizontally and reach the device 401 of the product 400. Thebarrier layer created by this method for the horizontal ingress path(i.e. Path-1 (404)) for the permeation of water vapor (or otherpermeants) for a 5-layer stack design is equivalent to a bi-layerbarrier consisting of a first inorganic layer (typically 50 nm inthickness and disposed adjacent to the footprint of device 401), asecond polymer layer (typically 800 nm in thickness), and a thirdinorganic layer (typically 200 nm in thickness labeled as 420 in FIG.4). Therefore, as shown, the resistance to horizontal permeation thatthis type of multilayer barrier design provides is equivalent to amultilayer barrier consisting of two inorganic layers and a polymerlayer disposed in-between (e.g. sandwiched between). Thus, while thevertical ingress comprises five inorganic barrier layers 402 and fourpolymeric layers 403, the horizontal ingress provides a much easierpermeation path that may determine the lifetime or degradation of thedevice 401.

Yet another approach using a multilayer barrier design for a product isshown in FIG. 5. The product 500 comprises a substrate 510, a device 501having a device footprint (which may comprise an active device area andan inactive device area) disposed over the substrate 510, and aplurality of inorganic 502 and polymer 503 layers disposed over andalong the sides of the footprint of device 501. The barrier layers aredeposited using increasingly larger sized masks for successive polymer503 and inorganic layers 502. In this approach the water vaportravelling horizontally along Path-1 (shown by the arrow labeled 504) inthe edge region of the product 500 faces the entire multilayer stack inits path before reaching the device 501 (unlike the products shown inFIGS. 3 and 4 described above). In this case, the edge seal provided bythe multilayer barrier comprising layers 502 and 503 to the water vapor(or other permeant) travelling across the bulk of the barrierhorizontally along Path-1 (504) is equivalent to the seal provided bythe multilayer barrier to the water vapor travelling vertically acrossthe bulk of the barrier (i.e. along Path-3 shown by the arrow 507).

However, even though the thickness of the polymer film per unit stack inthe horizontal direction (typically ˜1.0 mm each as shown in FIG. 5) ismuch greater than that of the thickness in the vertical direction(typically ˜0.8 μm each), the resistance to water vapor diffusion acrossthe layers is quite similar in both of the directions. The reason isthat, as described by G. L. Graff, Mechanisms of vapor permeationthrough multilayer barrier films: Lag time versus equilibriumpermeation, J. Appl. Phys., 96 (4), pp. 1840-1849 (2004), the effectivethickness to calculate the length (l) in the lag time calculation(t_(l)=l²/(6D)) is determined by either the thickness of the polymerfilm or the spacing of the defects in the inorganic film. In thevertical direction (i.e. along Path-3 (507)), the defect spacing of theinorganic film when assuming good permeation properties of the barrierlayers (e.g. on the order of couple hundred microns) is much larger thanthe polymer film thickness. In the horizontal direction (i.e. alongPath-1 (504)) the opposite is the case—that is, the defect spacing ofthe inorganic film is smaller than the polymer film thickness.Therefore, it is reasonable to assume that the edge ingress (e.g. Path-1(504)) for the product 500 fabricated using a progressively increasingmask size approach is comparable to the vertical permeation (i.e. alongPath-3 (507)) in the multilayer barrier.

Although two ingress paths were described above—i.e. horizontal Path-1(504) and vertical Path-3 (507)—there is another potential ingress pathfor permeants (Path-2 shown by the arrow 505). Path-2 (505) correspondsto water vapor permeation along the interface of the inorganic film withthe substrate 510. However, even if the interface permeation alongPath-2 (505) for the inorganic film is worse than bulk permeation in theinorganic film, the length of the ingress path is rather large acrossthe interface (e.g. approximately 5.0 mm as shown in FIG. 5), which istypically a large enough distance to make it a secondary ingress path incomparison to the ingress along Path-1 (504) (that is, permeants aremore likely to reach the device 501 through Path-1 (504) before theyreach the device 501 through Path-2 (505). One of the problemsassociated with the edge encapsulation approach shown in FIG. 5 of usingprogressively larger masks is the complexity associated with using theplurality of mask changes during fabrication—that is, each time a newmask is used during the fabrication process, it requires that the maskbe properly aligned (adding to the time and expense of the process). Inaddition, the perpendicular length (e.g. footprint) of the barriercomprising the multiple inorganic 502 and polymer 503 layers is large(i.e. approximately 5.0 mm wider than that of the device 501 of theproduct 500 on each side). This may thereby increase the non-active edgearea of the product around the footprint of device 501, which may, forinstance, correspond to the border area of the device (i.e. non-emittingregions for an OLED), and also unnecessarily increases product size toaccommodate the multiple barrier layers. Thus, the inventors have foundthat when attempting to reduce the edge ingress problem with aninorganic-polymer multilayer barrier, a long diffusion length may beneeded so as to delay the water vapor (or other permeant) permeating inthe horizontal direction (e.g. along Path-1 (504) or Path 2 (505)) alongthe edge of the product 500.

The inventors have discovered a barrier film material that comprises amixture of a polymeric material and a non-polymeric material that can beused as an edge sealant. It should be noted that, in general, thebarrier film comprising a mixture of a polymeric material and anon-polymeric material when used as an edge sealant can also be used inconjunction with a, for example, single layer barrier (i.e. a singlelayer barrier film), multilayer barrier (e.g. using multiple barrierlayers comprising different materials), or glass encapsulation andepoxy. This barrier film 606 functioning as an edge sealant may bedeposited in any suitable manner, including through the use of a singlechamber PE-CVD system.

A cross-section of the barrier film 606 that comprises a mixture of apolymeric material and a non-polymeric on a product 600 is shown in FIG.6. As described above, the two horizontal ingress paths for water vaporpermeation are shown (Path-1 (604), which is the ingress along the bulkof the barrier film 606, and Path-2 (605), which is the ingress alongthe interface of the barrier film 606 with the substrate 610). As wasdescribed above, the barrier film 606 providing an edge seal has afootprint (i.e. a perpendicular length l that extends from a side of thefootprint of device 601 to the edge of the barrier film 606 in adirection that is perpendicular to the side of the footprint of device601) that can be varied based on the longevity requirements of thedevice. The inventors have found that the perpendicular length (orfootprint) of the barrier film 606 can be made wider than the footprintof device 601 of the product 600 by 3.0 mm or less (preferably less than2.0 mm and more preferable less than 1.0 mm), while still providingadequate restriction on the ingress of environmental particulates. Itshould be noted that the barrier film 606 can be made wider than thefootprint of device 601 by more than 3.0 mm for extremely longshelf-life requirements or extremely harsh testing/storage conditions.As noted above, the exemplary barrier film that provides an edge sealmay be deposited in a single chamber system. Moreover, in someembodiments, barrier film may form both the edge seal as well as the topencapsulation barrier. This can reduce fabrication costs and complexitywhen fabricating an electronic device. However, embodiments are not solimited, and the barrier film 606 may be used in combination with one ormore encapsulation layers or components. Thus, the barrier film 606 thatforms an edge seal may act as a standalone component of the overallencapsulation package, as described in more detail with reference toFIGS. 11-14.

As was described above, with reference to FIG. 6, there are two basichorizontal permeation paths (Path-1 and Path-2) across the edge sealantfilm. With reference to FIG. 7, an exemplary product 700 is shown thatcomprises a substrate 710, a device 701 having a device footprint (whichmay comprise an active device area and an inactive device area) disposedover the substrate 710, a barrier film 706 disposed along the sides andover the top of the device 701. The ingress along Path-1 (704), which isthe horizontal bulk permeation, can be tested when the barrier film isused as both an edge sealant and as the top encapsulation film, as isthe case with the exemplary product 700 in FIG. 7. In such a case,Path-3 (707), which is also bulk permeation like Path-1 (704) but in thevertical direction, has a much shorter diffusion path for water vaporthan Path-1 (704). The length for Path-3 (707) in this example may beless than 10 μm, whereas the length (l) for Path-1 (704) (whichcorresponds to the perpendicular length of the barrier film) may beabout 1000 μm (i.e. 1.0 mm or more). If the barrier film that is used asan edge sealant works well as a top encapsulation layer, then anymeasurable contribution in edge ingress from water vapor traveling viaPath-1 (704) should be very low for a long duration of time because ofthe magnitude of the perpendicular length.

The inventors have tested an exemplary barrier film comprising a mixtureof a polymeric material and a non-polymeric material when used as thetop encapsulation layer and found that OLEDs encapsulated with thisexemplary barrier film operate at 100% performance (i.e. with nodegradation based on environmental conditions) for more than 500 hrs ofstorage at 85° C. and 85% RH. FIG. 8 shows the photographs of the activedevice area of a 2.0 mm² bottom-emission OLED encapsulated with the 9.0μm thick exemplary barrier film comprising a mixture of a polymericmaterial and a non-polymeric material used as a top encapsulation storedat 85° C. and 85% relative humidity (RH). In particular, FIG. 8 showspictures taken at different operating times (e.g. 0 hrs, 168 hrs, 240hrs, 410 hrs, 460 hrs, and 530 hrs). As shown in FIG. 8, no dark spotsdeveloped in the device even after 530 hrs in such relatively harshatmospheric conditions. Therefore, based on these results, it may beconcluded that for the exemplary barrier film that is being used as anedge sealant, any permeation along Path-1 (704) corresponding to thebulk permeation across the film does not cause device degradation for arelatively long duration of storage (e.g. in excess of 530 hrs). Itshould be noted that when there are particulates embedded in the barrierfilm when used as both an edge sealant and a top encapsulation, darkspots may be observed; however, the dark spots are the results ofpermeation of water vapor across the particulates and not the barrierfilm itself.

The inventors then tested the exemplary barrier film's edge sealingability by using different perpendicular lengths (i.e. edge lengths orfootprints, such as (l) shown in FIGS. 6 and 7) for several devices andthen measuring the lag time associated with those perpendicular lengthsin two separate experiments, the results of which are shown in FIGS.9(a) and (b). With reference to the first experiment shown in FIG. 9(a),for each of the three test devices, the barrier film comprising amixture of a polymeric material and a non-polymeric material was alsoused as the top encapsulation, but the thickness in the verticaldirection of the film was kept the same for each device. FIG. 9(a) showsthe photographs of the active device area of three 1.0 cm²bottom-emission OLEDs encapsulated by the exemplary barrier film havingtop encapsulation layer thickness of 9.0 μm and stored at 65° C. and 85%RH. The perpendicular lengths (l) (measured from a side of the devicefootprint of the device) of the barrier film used to edge seal thedevices shown in FIG. 9(a) are 1.0 mm, 2.0 mm, and 3.0 mm for each ofthe test devices, respectively (that is, the photos in column 901 are ofthe active device area of an exemplary OLED having a barrier film thathas a perpendicular length of 1.0 mm from a side of the devicefootprint; the photos of column 902 of the active area of an exemplaryOLED having a barrier film that has a perpendicular length of 2.0 mmmeasured from a side of the device footprint; and the photos in column903 are of the active area of an exemplary OLED having a barrier filmthat has a perpendicular length of 3.0 mm measured from a side of thedevice footprint). As was noted above, the perpendicular length in thiscase corresponds to the distance between the side of the devicefootprint (in this case, the side of an inactive device area that wasdisposed adjacent to the active device area of the OLED) and the edge ofthe barrier film (i.e. the footprint of the barrier film layer).Therefore, although the distance that the barrier film extends away fromthe device active area may be slightly larger than the perpendicularlength of the barrier film (i.e. by the thickness of the inactive devicearea), once water vapor reaches the organic layers or insulating layersthat may comprise the inactive device area, it would face no barrier inpropagating further into the active device area of the device.

The exemplary devices tested in FIG. 9(a) were larger area devicesrelative to the device tested with reference to FIG. 8 and therefore hadmore particulate contamination in the barrier films, resulting in thedevelopment of more dark spots. However, as can be seen in FIG. 9(a),the inventors did not find an appreciable difference in the edge ingressperformance of the three devices (that is, after 648 hrs, there isapproximately the same amount of dark spots in each device). Moreover,the inventors found that, even after a storage time of almost 1,000 hrsat 65° C. and 85% RH, the three devices appeared similar. Thus, as notedabove, the degradation in each of the three devices could be attributedto ingress based on the particulate contamination of the barrier film.In view of the results shown in FIG. 9(a), a barrier film having a 3.0mm perpendicular length or less (e.g. less than 2.0 mm, or less than 1.0mm) of this exemplary barrier film comprising a mixture of polymericmaterial and a non-polymeric material can provide adequate resistance tothe ingress of environmental permeants for at least 1,000 hrs or more at65° C. and 85% RH.

As was noted above, the horizontal bulk permeation across a 1.0 mmlength of the exemplary barrier film comprising a mixture of a polymericmaterial and a non-polymeric material would likely not be possible insuch a short duration of time. Therefore, the edge degradation of theseexemplary devices, which was generally held at acceptable levels forapproximately 1,000 hrs, is likely the result of ingress at theinterface (i.e. the ingress across the interface between the barrierfilm and the substrate across Path-2 discussed above). By further usingthe lag time calculation, the interface diffusion coefficient for watervapor for this particular exemplary barrier film comprising a mixture ofa polymeric material and a non-polymeric material (as used on testdevices tested in FIG. 9(a)) was determined to be about 4.6×10⁻¹⁰cm²/sec at 65° C. and 85% RH.

The inventors have further found that the interface diffusioncoefficient for products utilizing a barrier film comprising a mixtureof a polymeric material and a non-polymeric material as an edge seal maybe controlled in some instance by applying one or more techniques. Forexample, one such technique may be to change the nucleation density. Thenucleation density is the thin film growth technique that determines thethickness by which the growing film becomes dense and coherent. Ingeneral, before the film becomes dense it remains porous, and hencepermeable. The refractive index of the film prior to it becomingcompletely dense and coherent will be lower than that of the bulk film.L. S. Pan, D. R. Kania, Diamond: Electronic Properties and Applications,Springer, pp. 104-107, (1995), which is incorporated herein by referencein its entirety, describes that the nucleation density is inverselyproportional to the square of film thickness by which a film becomesdense. That means that to form a coherent and continuous film ofthickness (d), the nucleation density (N_(d))˜1/d². Thus, for anucleation density of 10¹⁰ cm⁻², the film would become continuous whenit reaches 100 nm.

In another similar experiment, the results of which are shown in FIG.9(b), the inventors again tested the exemplary barrier film's edgesealing ability by using three test devices having barrier films withdifferent perpendicular lengths (i.e. edge lengths or footprints, suchas (l) shown in FIGS. 6 and 7) and then measuring the lag timeassociated with those perpendicular lengths, but under harsherenvironmental conditions. For each of the experimental devices, thebarrier film comprising a mixture of a polymeric material and anon-polymeric material was also used as the top encapsulation, but thethickness in the vertical direction of the film was kept the same foreach device. The platform chosen for the test was coupons containing 4.0mm² calcium (Ca) buttons. FIG. 9(b) shows the photographs of the three4.0 mm² Ca buttons encapsulated by the exemplary barrier film having topencapsulation layer thickness of 9.0 μm and stored at 85° C. and 85% RH.The perpendicular lengths (l) (in this case, the perpendicular distancefrom the side of the Ca (i.e. the active device area because there wasno inactive device area) to the edge of the barrier film) of the barrierfilm used to edge seal the buttons shown in FIG. 9(b) are 1.0 mm, 2.0mm, and 3.0 mm for the buttons shown in the top, middle, and bottomrows, respectively. As noted above, these tests were even tougher thanthose described with reference to FIG. 9(a), as the active device area(i.e. Ca buttons) was 1.0, 2.0, and 3.0 mm away from the edge of thebarrier film. Once water vapor reaches the Ca button, it would start tobecome transparent due to formation of hydroxide.

The exemplary devices tested in FIG. 9(b) were facing an even moredaunting challenge than those shown in FIG. 9(a). As noted above, theperpendicular lengths were actually the distance of the active devicearea (i.e. Ca) from the edge of the barrier, and the devices were storedat 85° C. and 85% RH. Even under such harsh storage conditions, as canbe seen in FIG. 9(b), the inventors did not find an appreciabledifference in the edge ingress performance of the three devices (thatis, after 432 hrs, at 85° C. and 85% RH the buttons look the sameregardless of the thickness of edge seal). In view of the results shownin FIG. 9(b), a barrier film having a 3.0 mm perpendicular length orless (e.g. less than 2.0 mm, or less than 1.0 mm) of this exemplarybarrier film comprising a mixture of polymeric material and anon-polymeric material can provide adequate resistance to the ingress ofenvironmental permeants for at least 400 hrs or more at 85° C. and 85%RH.

In the exemplary devices described above, the barrier film that wasdeposited used HMDSO as the deposition precursor gas and oxygen as thenon-deposition gas (i.e. a gas which will not deposit any film when runthrough the plasma by itself) in a PE-CVD system. However, as describedin more detail below, other siloxanes or silazanes (or onrganosiliconsin general), for example, can be used as precursors. The exemplarybarrier film may be an intimate mixture of oxide with a little residualsilicone, which may be unoxidized precursor. The refractive index forthe exemplary barrier film may be a measure of its composition and tosome extent density. A refractive index close to that of thermal SiO₂would mean the film is more oxide like with high density. Exemplarydeposition process and conditions and similar considerations are knownin the art based patent applications U.S. Pat. No. U.S. Prov. Ser. No.61/086,047 and U.S. Pat. No. 7,968,146, which are each hereinincorporated by reference in their entireties. With increased nucleationdensity, even a thinner film may become continuous. Nucleation densitycan be controlled by various factors, such as deposition power,pressure, substrate temperature, and gas flow rates and ratio.Performing some surface treatment before the actual film deposition mayalso affect the interface. For examples, nitrogen plasma may leave somenitride bonds on the surface of a substrate and then a growing thin filmmay bond better to those bonds rather than with the substrate directly.

Composition and Fabrication of Exemplary Barrier Film

Provided below are exemplary compositions (and methods of fabricatingsuch compositions) of barrier film molecules and materials that may beused as an edge sealant in some embodiments as described above. In thisregard, exemplary embodiments of materials (and deposition processes)that may be used as an edge sealant are described in detail in U.S. Pat.No. 7,968,146 entitled “Hybrid Layers for Use in Coatings on ElectronicDevices or Other Articles,” which is hereby incorporated by referencesin its entirety for all purposes. The inventors have found that thematerials and methods described in U.S. Pat. No. 7,968,146, some ofwhich are provided below, may provide a barrier film that may bepreferred for use as an edge sealant for electronic devices. However,embodiments are not necessarily limited to the molecules and methodsdescribed therein.

In this regard, and as was noted above, in some embodiments, the barrierfilm may comprise a hybrid layer comprising a mixture of a polymericmaterial and a non-polymeric material. The hybrid layer may have asingle phase or multiple phases.

As used herein, the term “non-polymeric” may refer to a material made ofmolecules having a well-defined chemical formula with a single,well-defined molecular weight. A “nonpolymeric” molecule may have asignificantly large molecular weight. In some circumstances, anon-polymeric molecule may include repeat units. As used herein, theterm “polymeric” may refer to a material made of molecules that haverepeating subunits that are covalently linked, and that has a molecularweight that may vary from molecule to molecule because the polymerizingreaction may result in different numbers of repeat units for eachmolecule. Polymers may include, but are not limited to, homopolymers andcopolymers such as block, graft, random, or alternating copolymers, aswell as blends and modifications thereof. Polymers include, but are notlimited to, polymers of carbon or silicon.

As used herein, a “mixture of a polymeric material and a non-polymericmaterial” may refer to a composition that one of ordinary skill in theart would understand to be neither purely polymeric nor purelynon-polymeric. The term “mixture” is intended to exclude any polymericmaterials that contain incidental amounts of non-polymeric material(that may, for example, be present in the interstices of polymericmaterials as a matter of course), but one of ordinary skill in the artwould nevertheless consider to be purely polymeric. Likewise, this isintended to exclude any non-polymeric materials that contain incidentalamounts of polymeric material, but one of ordinary skill in the artwould nevertheless consider to be purely non-polymeric. In some cases,the weight ratio of polymeric to non-polymeric material in the hybridlayer is in the range of 95:5 to 5:95, and preferably in the range of90:10 to 10:90, and more preferably, in the range of 25:75 to 10:90.

The polymeric/non-polymeric composition of a layer may be determinedusing various techniques, including wetting contact angles of waterdroplets, IR absorption, hardness, and flexibility. In certaininstances, the hybrid layer has a wetting contact angle in the range 30°to 85°, and preferably, in the range of 30° to 60°, and more preferably,in the range of 36° to 60°. Note that the wetting contact angle is ameasure of composition if determined on the surface of an as-depositedfilm. Because the wetting contact angle can vary greatly bypost-deposition treatments, measurements taken after such treatments maynot accurately reflect the layer's composition. It is believed thatthese wetting contact angles are applicable to a wide range of layersformed from organo-silicon precursors. In certain instances, the hybridlayer has a nano-indentation hardness in the range 3 to 20 GPa, andpreferably, in the range of 10 to 18 GPa. In certain instances, thehybrid layer has a surface roughness (root-mean-square) in the range of0.1 nm to 10 nm, and preferably, in the range of 0.2 nm to 0.35 nm. Incertain instances, the hybrid layer, when deposited as a 4 mm thicklayer on a 50 mm thick polyimide foil substrate, is sufficientlyflexible that no microstructural changes are observed after at least55,000 rolling cycles on a 1 inch diameter roll at a tensile strain (ε)of 0.2%. In certain instances, the hybrid layer is sufficiently flexiblethat no cracks appear under a tensile strain (ε) of at least 0.35%(typically a tensile strain level which would normally crack a 4 mm puresilicon oxide layer, as considered by a person of ordinary skill in theart).

It should be noted that the term “mixture” is intended to includecompositions having a single phase as well as compositions havingmultiple phases. Therefore, a “mixture” excludes subsequently depositedalternating polymeric and non-polymeric layers. Put another way, to beconsidered a “mixture,” a layer should be deposited under the samereaction conditions and/or at the same time.

The hybrid layer may be formed by chemical vapor deposition using asingle precursor material (e.g. from a single source or multiplesources). As used herein, a “single source” of precursor material mayrefer to a source that provides all the precursor materials that arenecessary to form both the polymeric and non-polymeric materials whenthe precursor material is deposited by CVD, with or without a reactantgas. This is intended to exclude methods where the polymeric material isformed using one precursor material, and the non-polymeric material isformed using a different precursor material. As would be appreciated byone of skill in the art, a “single source” of precursor material mayinclude one or more containers (e.g. crucibles) that may be used duringthe process to heat or mix the chemicals that may form or contain asingle precursor material. For instance, a single precursor material maybe mixed or located in a plurality of containers and then vapordeposited. In general, by using a single precursor material, thedeposition process may be simplified. For example, a single precursormaterial will obviate the need for separate streams of precursormaterials and the attendant need to supply and control the separatestreams.

In general, the precursor material may be a single compound or a mixtureof compounds. Where the precursor material is a mixture of compounds, insome cases, each of the different compounds in the mixture is, byitself, able to independently serve as a precursor material. Forexample, the precursor material may be a mixture of hexamethyldisiloxane (HMDSO) and dimethyl siloxane (DMSO). Other precursors mayalso be utilized such as tetraethoxysilane (TEOS) or dimethyl siloxane(DMSO) or octamethylcyclotetrasiloxane orhexamethyldisilazane or otherorganosilanes or organosiloxanes and organosilazanes or their mixtures.

In some cases, plasma-enhanced CVD (PE-CVD) may be used for depositionof the hybrid layer. PE-CVD may be desirable for various reasons,including low temperature deposition, uniform coating formation, andcontrollable process parameters. Various PE-CVD processes that aresuitable for use in forming a hybrid layer that may comprise a barrierlayer for an edge sealant are known in the art, including those that useRF energy to generate the plasma.

The precursor material may be a material that is capable of forming botha polymeric material and a non-polymeric material when deposited bychemical vapor deposition. Various such precursor materials are suitablefor use in providing a barrier film comprising a hybrid layer and may bechosen for their various characteristics. For example, a precursormaterial may be chosen for its content of chemical elements, itsstoichiometric ratios of the chemical elements, and/or the polymeric andnon-polymeric materials that are formed under CVD. For instance,organo-silicon compounds, such as siloxanes, are a class of compoundssuitable for use as the precursor material. Representative examples ofsiloxane compounds include hexamethyl disiloxane (HMDSO) and dimethylsiloxane (DMSO). When deposited by CVD, these siloxane compounds areable to form polymeric materials, such as silicone polymers, andnon-polymeric materials, such as silicon oxide. The precursor materialmay also be chosen for various other characteristics such as cost,non-toxicity, handling characteristics, ability to maintain liquid phaseat room temperature, volatility, molecular weight, etc.

Other organo-silicon compounds suitable for use as a precursor materialinclude methylsilane; dimethylsilane; vinyl trimethylsilane;trimethylsilane; tetramethylsilane; ethylsilane; disilanomethane;bis(methylsilano)methane; 1,2-disilanoethane;1,2-bis(methylsilano)ethane; 2,2-disilanopropane;1,3,5-trisilano-2,4,6-trimethylene, and fluorinated derivatives of thesecompounds. Phenyl-containing organo-silicon compounds suitable for useas a precursor material include: dimethylphenylsilane anddiphenylmethylsilane. Oxygen containing organo-silicon compoundssuitable for use as a precursor material include:dimethyldimethoxysilane; 1,3,5,7-tetramethylcyclotetrasiloxane;1,3-dimethyldisiloxane; 1,1,3,3-tetramethyldisiloxane;1,3-bis(silanomethylene)disiloxane; bis(1-methyldisiloxanyl)methane;2,2-bis(1-methyldisiloxanyl) propane;2,4,6,8-tetramethylcyclotetrasiloxane; octamethylcyclotetrasiloxane;2,4,6,8,10-pentamethylcyclopentasiloxane;1,3,5,7-tetrasilano-2,6-dioxy-4,8-dimethylene;hexamethylcyclotrisiloxane; 1,3,5,7,9-pentamethylcyclopentasiloxane;hexamethoxydisiloxane, and fluorinated derivatives of these compounds.Nitrogen-containing organosilicon compounds suitable for use as aprecursor material include: hexamethyldisilazane;divinyltetramethyldisilizane; hexamethylcyclotrisilazane;dimethylbis(N-methylacetamido) silane;dimethylbis-(N-ethylacetamido)silane;methylvinylbis(N-methylacetamido)silane; methylvinylbis(Nbutylacetamido)silane; methyltris(N-phenylacetamido) silane;vinyltris(N-ethylacetamido)silane; tetrakis(Nmethylacetamido) silane;diphenylbis(diethylaminoxy) silane; methyltris(diethylaminoxy)silane;and bis (trimethylsilyl)carbodiimide.

When deposited by CVD, the precursor material may form various types ofpolymeric materials in various amounts, depending upon the type ofprecursor material, the presence of any reactant gases, and otherreaction conditions. The polymeric material may be inorganic or organic.For example, where organo-silicon compounds are used as the precursormaterial, the deposited hybrid layer may include polymer chains of Si—Obonds, Si—C bonds, or Si—O—C bonds to form polysiloxanes,polycarbosilanes, and polysilanes, as well as organic polymers.

When deposited by CVD, the precursor material may form various types ofnon-polymeric materials in various amounts, depending upon the type ofprecursor material, the presence of any reactant gases, and otherreaction conditions. The non-polymeric material may be inorganic ororganic. For example, where organo-silicon compounds are used as theprecursor material in combination with an oxygen-containing reactantgas, the non-polymeric material may include silicon oxides, such as SiO,Si0₂, and mixed-valence oxides SiO_(x). When deposited with anitrogen-containing reactant gas, the non-polymeric material may includesilicon nitrides (SiN_(x)). Other non-polymeric materials that may beformed in some instances include silicon oxycarbide and siliconoxynitrides.

When using PE-CVD, the precursor material may be used in conjunctionwith a reactant gas that reacts with the precursor material in thePE-CVD process. The use of reactant gases in PE-CVD is known in the artand various reactant gases are suitable for use in the presentinvention, including oxygen containing gases (e.g., 0₂, ozone, water)and nitrogen-containing gases (e.g., ammonia). The reactant gas may beused to vary the stoichiometric ratios of the chemical elements presentin the reaction mixture. For example, when a siloxane precursor materialis used with an oxygen or nitrogen-containing reactant gas, the reactantgas will change the stoichiometric ratios of oxygen or nitrogen inrelation to silicon and carbon in the reaction mixture. Thisstoichiometric relation between the various chemical elements (e.g.,silicon, carbon, oxygen, nitrogen) in the reaction mixture may be variedin several ways. One way is to vary the concentration of the precursormaterial or the reactant gas in the reaction. Another way is to vary theflow rates of the precursor material or the reactant gas into thereaction. Another way is to vary the type of precursor material orreactant gas used in the reaction.

Changing the stoichiometric ratios of the elements in the reactionmixture can affect the properties and relative amounts of the polymericand non-polymeric materials in the deposited hybrid layer. For example,a siloxane gas may be combined with varying amounts of oxygen to adjustthe amount of non-polymeric material relative to the polymeric materialin the hybrid layer. By increasing the stoichiometric ratio of oxygen inrelation to the silicon or carbon, the amount of non-polymeric material,such as silicon oxides, may be increased. Similarly, by reducing thestoichiometric ratio of oxygen, the amount of silicon andcarbon-containing polymeric material may be increased. The compositionof the hybrid layer may also be varied by adjusting other reactionconditions. For example, in the case of PE-CVD, process parameters suchas RF power and frequency, deposition pressure, deposition time, and gasflow rates can be varied.

Thus, by using the exemplary methods as described above, it is possibleto form a hybrid layer of hybrid polymeric/non-polymeric character andhaving characteristics suitable for use in various applications,particular as a barrier film to reduce edge ingress of permeates. Suchcharacteristics of the barrier film may include optical transparency(e.g., in some cases, the hybrid layer may be optically transparent orsemi-transparent), impermeability, flexibility, thickness, adhesion, andother mechanical properties. For example, one or more of thesecharacteristics may be adjusted by varying the weight % of polymericmaterial in the hybrid layer, with the remainder being non-polymericmaterial. For instance, to achieve a desired level of flexibility andimpermeability, the wt % of polymeric material may preferably be in therange of 5 to 95%, and more preferably in the range of 10 to 25%.However, other ranges are also possible depending upon the application.

EXEMPLARY EMBODIMENTS

Described below are exemplary embodiments of products that comprise abarrier film comprising a mixture of a polymeric material and anon-polymeric material as an edge sealant. The embodiments describedherein are for illustration purposes only and are not thereby intendedto be limiting. After reading this disclosure, it may be apparent to aperson of ordinary skill in the art that various components and/orfeatures as described below may be combined or omitted in certainembodiments, while still practicing the principles described herein.

In some embodiments, a first product is provided. The first product mayinclude a substrate, a device having a device footprint disposed overthe substrate, and a barrier film disposed over the substrate andsubstantially along a side of the active area. The barrier film maycomprise a mixture of a polymeric material and non-polymeric material.The barrier film may have a perpendicular length that is less than orequal to 3 mm from the side of the device footprint.

As described above, the “perpendicular length” of the barrier film mayrefer to the distance from a portion of the barrier film that isdisposed closest to the footprint of the device (e.g. adjacent to theactive device area or inactive device area) to another portion of thebarrier film that is disposed farthest away from the device footprint(e.g. the edge of the barrier film) in a direction that is perpendicularto the side of the device footprint and parallel to the surface of thesubstrate that the barrier film is disposed over.

As used in this context, “substantially along a side” of the devicefootprint does not necessarily require that the barrier film be disposeddirectly adjacent to the device footprint. Moreover, this does notpreclude the barrier film from being disposed in other locationsrelative to the device, including embodiments where a portion of thebarrier film may be disposed over one or more layers (such as a cathode,electron transport layer, hole transport layer, etc. of an OLED) of thedevice.

The use of the term “a perpendicular length” in the phrase “a barrierfilm may have a perpendicular length” is generally meant to coverembodiments where one portion of the barrier film may be deposited orotherwise fabricated so as to have a perpendicular length that isgreater than 3.0 mm, so long as the edge of any portion of the barrierfilm is disposed so as at have a perpendicular distance that is lessthan 3.0 mm from a side of the footprint of the device. As was describedabove, the lifetime and performance of a device based on the ingress ofcontamination by outside particulates typically depends on the shortestor lease resistive path of ingress into the sensitive components of adevice. The barrier film provided herein may be utilized such that theshortest part of horizontal ingress may be less than 3.0 mm (preferablyless than 2.0 mm, and more preferably less than 1.0 mm).

In general, products that reduce the size of the barrier film that formsthe edge seal (i.e. that reduce the perpendicular length) may providefor a reduction in the amount of border area (e.g. “dead space”) of thedevice. Moreover, through the use of exemplary barrier film materials,embodiments provided herein may reduce the size of the non-active edgearea without substantially affecting device performance or degradation.The exemplary barrier film may restrict both horizontal bulk permeationand permeation across the interface between the barrier film and thesubstrate. Reducing the non-active edge area of a device created by anedge seal may provide additional space for other electronic componentsof the device, larger displays, a reduction in the border area betweenemitting devices (which may make such areas less noticeable when, forinstance, multiple displays or panels are tiled), or otherwise increasethe efficiency of manufacturing or layout of such devices. Moreover,embodiments that utilize a single barrier film layer (e.g. that may bedeposited in a single deposition step) to encapsulate the device mayprovide a more efficient and less time consuming fabrication process incomparison to products that utilize multilayer barriers (such as thosedescribed above with reference to FIGS. 3-5). However, embodiments arenot so limited, and some products that have a barrier film thatcomprises a mixture of a polymeric material and non-polymeric materialmay also utilize multiple barrier or encapsulation layers (such as FIGS.11-14).

In some embodiments, in the first product as described above, the devicefootprint may comprise an active device area and an inactive devicearea. In some embodiments, the barrier film may have a perpendicularlength that is less than or equal to 3.0 mm from the side of theinactive device area. That is, the barrier film may be disposed so as tobe adjacent to a side of the inactive device area and extend in adirection perpendicular to the side of the inactive area (and therebythe side of the device footprint of the device) by less than 3.0 mm(preferably less than 2.0 mm, and more preferably less than 1.0 mm). Insome embodiments, the barrier film may not extend to a distance ofgreater than 3.0 mm from a side of the active device area. That is, insome instances, the barrier film may not be disposed adjacent to theside of the active device area (e.g. because the active device area maybe surrounded by inactive device area) and thereby the perpendicularlength of the barrier film may not correspond to the distance that theedge of the barrier film is disposed away from the side of the activedevice area. In some such embodiments, the total distance of theperpendicular length of the barrier film and the thickness of theinactive device area may be less than 3.0 mm from a side of the activearea (preferably less than 2.0 mm; and more preferably less than 1.0mm). In this manner, the border area of the device may be less than 3.0mm (preferably less than 2.0 mm and more preferably less than 1.0 mm).

In some embodiments, in the first product as described above, the devicefootprint may comprise an active device area, and the barrier film mayhave a perpendicular length that is less than or equal to 3.0 mm fromthe side of the active device area (preferably less than 2.0 mm and morepreferably less than 1.0 mm). That is, in some embodiments, the devicemay not comprise an inactive device area (or at least a portion of thedevice may not comprise an inactive device area), and thereby thebarrier film may extend from the side of the active device area.

Examples of these concepts are illustrated in FIGS. 15-17. Withreference to FIG. 15, a top view of an exemplary product 1500 comprisingan OLED is shown. The product 1500 comprises a device having a devicefootprint 1501 disposed over the substrate 1510. The device footprint1501 comprises an active device area 1550 and an inactive device area1551. The product 1500 further comprises a cathode 1543 that is disposedpartially within the device footprint 1501, but that also includes acathode contact 1544 that extends away from the device footprint 1501(to the right in FIG. 15), and an anode 1540 that is disposed partiallywithin the device footprint 1501, but that has an anode contact 1541that extends away from the device footprint 1501 (to the left in FIG.15). The anode contact 1541 and the cathode contact 1544 may form one ormore electrical contacts with electrical components (such as powersource, drive circuitry, etc.) and can extend beyond the edge of thebarrier film 1506 or be encapsulated by the barrier film 1506.

The device further comprises organic layers 1545 that are partiallydisposed within the active device area 1550 and the inactive device area1551 of the device. The device further comprises a grid layer 1546(which could comprise organic or inorganic material) that is shown ascomprising a part of the inactive device area 1551, and a barrier film1506 that is shown as comprising the non-device edge area 1553, as wellas being disposed over the device and portions of the anode contact 1541and cathode contact 1544. The non-device edge area 1553 and the inactivedevice area 1551 are shown as comprising the border (dead space) area1552.

With reference to FIG. 16, the cross-section along the line A-A′ of theexemplary product 1500 in FIG. 15 is shown. The product 1600 comprises adevice disposed over the substrate 1610 having a device footprint 1601.The device footprint 1601 comprises an active device area 1650 and aninactive device area 1651. The product 1600 further comprises a cathode1643 that is disposed partially within the device footprint 1601, butthat also includes a cathode contact 1644 that extends away from thedevice footprint 1601 (to the right in FIG. 16), and an anode 1640 thatis disposed partially within the device footprint 1601, but that has ananode contact 1641 that extends away from the device footprint 1601 (tothe left in FIG. 16). The device further comprises organic layers 1645that are partially disposed within the active device area 1650 andinactive device area 1651, a grid layer 1646 (which could compriseorganic or inorganic material) that is shown as comprising a part of theinactive device area 1651, and a barrier film 1606 that is shown ascomprising the non-device edge area 1653, as well as being disposed overthe device and portions of the anode contact 1641 and cathode contact1644. The non-device edge area 1653 and the inactive device area 1651are shown as comprising the border (dead space) area 1652. Thus, in thisexample, the grid layer 1646 is shown as being disposed over anodecontact 1641 (on the left side of the device) and over a portion of theanode 1644 and adjacent to substrate 1610 on the right side of thedevice. In this manner, the inactive device area 1651 may comprise twoelectrodes and the organic layer(s), this portion of the device may notemit light (e.g. for an OLED) and thereby does not comprise a part ofthe active device area 1650.

As shown in FIG. 16, in some embodiments, the barrier film 1603 may bedisposed adjacent to the inactive device area 1651 (e.g. grid layer 1646on the left side of the device in FIG. 16). Thus, the perpendicularlength of the barrier film 1606 may correspond to the distance thebarrier film 1606 extends away from the inactive device area 1651. Onthe opposite side of the device, the cathode contact 1644 extends beyondthe grid layer 1646 (such that the grid layer 1646 insulates the anode1640 and the cathode contact 1644). The barrier film 1606 is shown asbeing disposed adjacent to the cathode contact 1644 and extends awayfrom the device footprint 1601. Thus, in this example, although thebarrier film 1606 is disposed along a side of the device footprint 1601(e.g. along the side of the inactive device area 1651) it is notdisposed adjacent to the inactive device area 1651. As noted above,

With reference to FIG. 17, a cross-sectional view along the line B-B′ ofthe exemplary product 1500 shown in FIG. 15 is shown. The product 1700comprises a device disposed over the substrate 1710 having a devicefootprint 1701. The device footprint 1701 comprises an active devicearea 1750 and an inactive device area 1751. The product 1700 furthercomprises a cathode 1743 that is disposed entirely within the devicefootprint 1701 (unlike FIG. 16) and an anode 1740 that is disposedentirely within the device footprint 1701 (again unlike FIG. 16). Thatis, the cathode and anode may, but need not, have contacts that extendbeyond the device footprint 1701 in more than one direction. The devicecomprises organic layers 1745 that are partially disposed within theactive device area 1750 and inactive device area 1751, a grid layer 1746(which could comprise organic or inorganic materials) that is shown ascomprising a part of the inactive device area 1751, and a barrier film1706 that is shown as comprising the non-device edge area 1753, as wellas being disposed over the device. In this example, the barrier film1706 is shown as being disposed along a side of the inactive area 1751of the device footprint 1701 on both sides of the device.

It should be noted that some of the additional detail and componentsshown in FIG. 1507 were omitted from the FIGS. 4-7 and 10-14 forillustration purposes only. That is, the embodiments shown in each ofthose figures could comprise some or all of the additional layers ormaterials shown and described in more detail with reference to FIGS.15-17. However, these embodiments were described and shown at ahigh-level to demonstrate basic design and implementation concepts, andshould thereby not be considered limiting.

In some embodiments, in the first product as described above, thebarrier film may comprise a mixture of a polymeric silicon and inorganicsilicon. The “mixture of polymeric silicon and inorganic silicon” wasdescribed above in detail, particular with reference to U.S. Pat. No.7,968,146. The inventors have found that such a mixture may provide abarrier film that may be capable of restricting ingress of moisture orwater vapor (or other environmental contaminants) while maintainingrelatively small dimensions for the film. In the case of an edgesealant, the inventors have discovered that such materials may provideadequate performance while having a perpendicular length of less than3.0 mm (preferably less than 2.0 mm; and more preferably less than 1.0mm) from the side of the device footprint. Previously, edge seals oftencomprised multiple layers to achieve adequate performance, which istypically inefficient both to manufacture such devices and also createsrelatively large non-active edge areas (and thereby border areas) on aproduct.

In some embodiments, the mixture of polymeric silicon and inorganicsilicon may be substantially uniform across the layer. By“substantially,” it is generally meant that the film comprises a mixturethat does not vary by more than 5% across the layer. As noted above, thebarrier film may be deposited in a single process, which may increasemanufacturing efficiency. The 5% variance may account for minorfluctuations across the product that may occur during the manufacturingprocesses. For products that comprise a light emitting device (such as alighting panel or display), a uniform layer may be preferred because itmay reduce micro-cavity effects or other effects associated withmultiple layers having different optical properties. However,embodiments are not so limited, and in some instances, the barrier filmmay vary across the layer (such as a graded layer), which could, forinstance, increase the resistance to ingress across the bulk of thebarrier layer.

In some embodiments, in the first product as described above, thebarrier film may have a perpendicular length that is less than or equalto 2.0 mm. In some embodiments, the barrier film may have aperpendicular length that is less than or equal to 1.0 mm. As wasdescribed above, the barrier film comprising a mixture of a polymericmaterial and a non-polymeric material when utilized as an edge seal mayreduce the size of the non-active edge area of the product in at leastone direction, while still providing for adequate lifetime andperformance of the device. In particular, the inventors have found thatusing the barrier film comprising a mixture of a polymeric material andnon-polymeric material provides good performance when having aperpendicular length of less than 2.0 mm (and may even have similarperformance at less than 1.0 mm). This is a substantial improvement overthe distances typically required by multilayer products that werepreviously used, such as those shown in FIGS. 3-5.

In some embodiments, in the first product as described above, thebarrier film may not have a perpendicular length that is greater than3.0 mm. That is, some embodiments may not have a portion of the barrierfilm that is deposited or disposed at a location on the substrate so asto have a perpendicular distance that is greater than 3.0 mm from theside of the device footprint. For example, the barrier film comprising amixture of a polymeric material and a non-polymeric material may bedeposited around all of the sides of the device footprint at a distanceof less than 3.0 mm. This may provide products that have a minimumamount of non-active edge area over the substrate, thereby allowing, forexample, a display or lighting panel to extend closer to the edge of theproduct. Moreover, the inventors have unexpectedly found that suchbarrier films used as edge sealants have comparable performance when thebarrier film may not have a perpendicular length that is greater than2.0 mm (and preferably when the barrier film does not have aperpendicular length that is greater than 1 mm) from the side of thedevice footprint. Despite the reduction in the length of ingress pathfor such embodiments, as described with reference to FIGS. 9(a) and (b)and the corresponding experiments, the inventors have found an equalamount of contamination in comparable devices over an extended period oftime in hostile environmental conditions. Thus, the inventors havediscovered that the use of the barrier film comprising a mixture of apolymeric material and a non-polymeric material as an edge seal may beeffective with perpendicular distances less than 3.0 mm (and even lessthan 2.0 mm or 1.0 mm).

In some embodiments, in the first product as described above, thebarrier film may not have a perpendicular length that is greater than3.0 mm or less than 1.0 mm. In some embodiments, the barrier film maynot have a perpendicular length that is greater than 2.0 mm or less than0.5 mm. That is, some embodiments of products may have an edge sealanthaving a range of perpendicular lengths around the device footprint, butin general it may be preferred that the range be great enough to provideadequate performance for the device, but sill have small enoughdimensions so as to reduce the non-active edge area of the product.

In some embodiments, in the first product as described above, thebarrier film may comprise a substantially uniform material. As used inthis context, “uniform” may refer to when the material of the barrierlayer comprises the same materials or concentration of materials acrossthe layer. That is, “uniform” does not require that the film necessarilycomprise only a single material, but could comprise a layer that has thesame, or substantially the same, mixture across the layer. The use ofthe term “substantially” in this context is to account for minorvariations that may occur based on manufacturing error or imperfections,but generally refers to uniformity that does not vary by more than 5%across the film. In some embodiments, the barrier film may comprise auniform material—that is, there may be less than 1% variation across thefilm. The use of uniform (or substantially uniform) barrier films asedge sealants may be the result of using a single deposition process fordepositing the film, which may reduce the costs of the fabricationprocess by reducing the number of fabrication steps/conditions.

In some embodiments, in the first product as described above, thebarrier film may comprise a mixture of an oxide and polymeric silicone.In some embodiments, the barrier film may comprise at least 40%inorganic silicon. The inventors have found that the use of organicsilicon and polymeric silicon may provide properties that arewell-suited for forming an edge seal to prevent the ingress ofcontaminants in the device. It should be noted that the use of the term“at least” in this context does not require that the mixture orcomposition of the film be uniform—so long as there are no portions ofthe layer that comprise less than 40% inorganic silicon. In someembodiments, the barrier film may comprise at least 60% inorganicsilicon. In some embodiments, the barrier film may comprise at least 80%inorganic silicon. As was noted above, the mixture concentrations andmaterials may be fine-tuned or selected to have desired characteristicsso that the edge seal may be determined based on the particularapplication and environmental conditions expected for the device, aswould be understood by one of ordinary skill in the art after readingthis disclosure.

In this regard, in some embodiments, in the first product as describedabove, a surface of the barrier film may be disposed adjacent to asurface of the substrate to form a first interface. The ratio of theindex of refraction of the bulk of the barrier film and the index ofrefraction of a portion of the barrier film that is within 10 nm of theinterface may be between 0.9993 and 0.9247. The “index of refraction ofthe bulk” of the barrier film may refer to the index of refractionacross the barrier film layer (i.e. index of refraction across the filmin a direction corresponding to a path that light that isperpendicularly incident on the film propagates through the layer). Ingeneral, the inventors have found that for products that may comprise alight emitting active area (such as an OLED) or any other transparent orsemi-transparent device, it may be beneficial to deposit a barrier filmsuch that the index of refraction of the film is similar to thesubstrate (particularly near the interface with the substrate). This mayreduce the amount of light that may be trapped between the barrier filmand the substrate and thereby increase the efficiency of the device.Moreover, less light may be color shifted or otherwise distorted whenpassing through the edge seal and then the substrate.

In some embodiments, in the first product as described above, where asurface of the barrier film is disposed adjacent to a surface of thesubstrate to form a first interface, the index of refraction of aportion of the barrier film that is within 10 nm of the interface may bebetween 1.35 and 1.459. In many embodiments, the substrate material maybe transparent or semi-transparent such as a glass or plastic materialand will typically have an index of refraction between 1.35 and 1.459.As was noted above, it is generally preferred (at least for devicescomprising an emissive active area) that the index of refraction of thebarrier film and the substrate are similar.

In some embodiments, in the first product as described above, where asurface of the barrier film is disposed adjacent to a surface of thesubstrate to form a first interface, the barrier film may comprise amaterial having a bulk diffusion coefficient of water vapor of less than10⁻¹³ cm²/sec. The bulk diffusion coefficient of the barrier film mayrefer to the rate of ingress of water vapor in the horizontal directionacross the film (e.g. along Path-1 (704) in FIG. 7) or in the verticaldirection (e.g. along Path-3 (707) in FIG. 7). The inventors have foundthat a bulk diffusion coefficient of less than 10⁻¹³ cm²/sec isgenerally sufficient to provide adequate device lifetime andperformance, even in hostile environments as described above. In someembodiments, the diffusion coefficient of water vapor at the firstinterface may be between 10⁻⁸ cm²/sec and 10⁻¹³ cm²/sec when exposed toan ambient temperate of 65° C. and relative humidity of 85%. Thediffusion coefficient at the interface corresponds to the ingress ofmoisture across the interface between the film and the substrate (e.g.along Path-2 (705) in FIG. 7), which may be the limiting factor in someembodiments for device lifetime or performance based on environmentalcontaminants. As was noted above, the inventors have found that abarrier film that comprises a mixture of a polymeric material andnon-polymeric material may provide a sufficient diffusion coefficient atthe interface for adequate device performance, even when the ingresspath is less than 3.0 mm (preferably less than 2.0 mm; and morepreferably less than 1.0 mm). As a person of ordinary skill in the artwould understand, the properties of the edge seal (including thediffusion coefficient) may be tuned by adjusting the depositionconditions (including the precursor material) as was described above, toachieve a desired set of properties for the barrier film for aparticular device or application.

In some embodiments, in the first product as described above, where asurface of the barrier film is disposed adjacent to a surface of thesubstrate to form a first interface, the barrier film may comprise amaterial having a bulk diffusion coefficient of water vapor. The ratioof the bulk diffusion coefficient of water vapor of the barrier film anda diffusion coefficient of water vapor near the first interface may bebetween 1 and 10⁻⁵. That is, for instance, the bulk diffusioncoefficient for the barrier film (e.g. the ingress rate along Path-1(704) in FIG. 7) may be equal to or less than the diffusion coefficientat or near the interface with the substrate (e.g. the ingress rate alongPath-2 (705) in FIG. 7). As was noted above, in some embodiments, theingress of water vapor along the interface may be the limiting factor indetermining the lifetime or degradation of the device. The inventorshave found that by tuning the properties of the barrier film, it ispossible to adjust both the diffusion coefficient of the bulk material,as well as the diffusion coefficient along the interface with thesubstrate. In some embodiments, the ratio of the bulk diffusioncoefficient of water vapor of the barrier film and a diffusioncoefficient of water vapor within 10 nm of the first interface isbetween 1 and 10⁻⁵.

In some embodiments, in the first product as described above, the firstproduct may further comprise a conductive layer disposed over the device(such as a layer of the device—e.g. an electrode). In some embodiments,a portion of the barrier film may be disposed at least partially overthe conductive layer. In some embodiments, a portion of the barrier filmmay be disposed over the entire conductive layer. That is, for instanceand as shown in FIGS. 7 and 15-17, in some embodiments, the barrier filmmay be used both as an edge seal and as an encapsulation layer over theentire device. This may reduce the cost and complexity of thefabrication process, as the barrier film could be deposited in a singlestep using a mask that is larger than the mask used for depositing thedevice footprint. Moreover, as noted above, the barrier film comprisinga mixture of a polymeric material and non-polymeric material may have alow ingress rate based on the bulk diffusion coefficient and may therebybe utilized as an encapsulation layer for the device.

However, embodiments are not so limited, and in some instances, in thefirst product as described above where the device comprises a conductivelayer disposed over one or more device layers, a top sealant layer maybe disposed over the conductive layer. The top sealant layer and thebarrier film may comprise different materials. Thus, the barrier filmcomprising a mixture of a polymeric material and non-polymeric materialmay be used in conjunction with other materials to encapsulate thedevice of the product. Examples of such embodiments are shown in FIGS.11-14 and described in detail below.

In some embodiments, in the first product as described above, the firstproduct may comprise a border area. The border area may have a thicknessthat is less than 3.0 mm (preferably less than 2.0 mm; and morepreferably less than 1.0 mm) and may depend at least in part on the sizeof the barrier film and the size of the inactive device area. As wasnoted above, embodiments described herein that utilize a barrier filmcomprising a mixture of a polymeric material and non-polymeric materialmay have an effective edge seal against the ingress of environmentalcontaminants such that the size of the edge seal may be reduced. Thismay thereby allow for products to have smaller non-device edge areasaround the active device area and inactive device areas of the device(thereby decreasing the size of the border area). Thus, as noted above,in some embodiments, in the first product as described above, where thefirst product comprises a non-device edge area, the non-device edge areamay have a thickness that is less than 3.0 mm. In some embodiments, thenon-active edge area may have a thickness that is less than 2.0 mm(preferably less than 1.0 mm).

In some embodiments, the first product as described above may comprise aconsumer device. In some embodiments, the first product may compriseanyone of: a solar cell, a thin film battery, an organic electronicdevice, a lighting panel or a lighting source having a lighting panel, adisplay or an electronic device having a display, a mobile phone, anotebook computer, a tablet computer, or a television. In general, anyproduct that uses a thin film to encapsulate or protect sensitivecomponents may use the barrier film described herein comprising amixture of polymeric material and non-polymeric material as an edgeseal.

In some embodiments, in the first product as described above, the devicemay comprise an organic layer. In some embodiments, the organic layermay comprise an electro-luminescent material. In some embodiments, thedevice may comprise an OLED. However, as noted above, while theinventors have found that the barrier film may perform particularly wellas an edge sealant for an organic device (and thereby some of theexamples and descriptions provided herein may reference OLEDs),embodiments are not so limited.

As was noted above, the barrier film that may be used as an edge sealantfilm may also be used in some embodiments as a top encapsulation film asshown in the exemplary embodiment in FIG. 10 or in conjunction withother top encapsulations as shown in FIGS. 11-14.

FIG. 10 shows an exemplary product 1000 that uses the barrier film as anedge seal and as a top sealant. The product 1000 comprises a substrate1010, a device 1001 having a device footprint disposed over thesubstrate 1010, and a barrier film 1006 disposed along the sides of thedevice footprint and over the top of the device 1001. The barrier film1006 is shown as having a perpendicular length of 1.0 mm. The twoingress paths (Path-1 (1004) and Path-2 (1005)) are shown. As notedabove, such embodiments may provide for increased efficiency in themanufacturing process, as both the top encapsulation and the edgesealant comprise the same material (i.e. barrier film 1006).

As shown in FIG. 11, the edge sealant film 1106 can be used inconjunction with a single layer top encapsulation film. In this regard,the exemplary product 1100 comprises substrate 1110, a device 1101disposed over the substrate 1110 having a device footprint, a barrierfilm 1106 disposed along the sides of the device footprint of device1101, and a second barrier layer (or top encapsulation layer) 1108disposed over the device footprint 1101. As noted above, utilizing thebarrier film comprising a mixture of a polymeric material andnon-polymeric material may enable the footprint of the single layerbarrier film 1106 to be kept very close to that of the footprint ofdevice 1101 (i.e. the perpendicular length of the barrier film 1106extending away from the side of the footprint of device 1101 may be keptrelatively small). In some embodiments, after the top encapsulationlayer 1108 is formed or deposited, the barrier film 1106 that forms theedge seal may be deposited. The barrier film 1106 can be deposited justalong the sides of the footprint of device 1101 as shown in FIG. 11 orit can also cover the top encapsulation layer 1108 depending on theneeds of the device and the manufacturing requirements (that is, it maybe more efficient and less expensive to deposit the barrier film 1106 asa blanket layer over the entire substrate 1110, rather than having toselectively deposit the barrier film 1106 only along the sides of thefootprint of device 1101). In either embodiment, the use of the barrierfilm 1106 as the edge sealant may reduce the overall footprint of theencapsulation (i.e. the top encapsulation barrier 1108 and the edgesealant 1106). As shown in FIG. 11, in some embodiments, theperpendicular length of the barrier film 1106 may be equal to or lessthan 1.0 mm (i.e. the footprint of the barrier film 1106 may be lessthan 1.0 mm wider than the footprint of device 1101 on one or moresides). Similar to FIG. 11, the same principle is shown in FIG. 12 wherethe barrier film 1206 is used as the edge sealant for the device 1201disposed over the substrate 1210 in conjunction with a multilayerbarrier film (comprising inorganic 1202 and polymer 1203 layers) used asthe top encapsulation. In this example, the barrier film 1206 is shownas having a perpendicular length of 1.0 mm.

As shown in FIG. 13, the barrier film may also be used along with glassencapsulation. In this regard, FIG. 13 shows an exemplary product 1300comprising a substrate 1310, a device 1301 disposed over the substrate1310 having a device footprint, a barrier film 1306 disposed along thesides of the footprint of the device 1301, and a top encapsulationcomprising a glass layer 1311 and an epoxy 1312 (e.g. to couple theglass layer 1311 to the substrate 1310) disposed over the device 1301.In general, glass encapsulation typically suffers from the problem ofedge ingress when the epoxy 1312 is used as the edge seals. If the epoxy1312 can be deposited directly over the device 1301, the glassencapsulation 1311 may then be restricted to being disposed over thedevice 1301 only. In such a case, as shown in FIG. 13, the barrier film1306 may be used as an edge sealant to cover the edges of the glassencapsulation 1311 and the epoxy seals 1312 to provide the edge seal forthe glass encapsulation.

However, in some instances, the epoxy cannot be deposited directly ontop of the device (or the layers disposed thereon). This is illustratedin FIG. 14, which shows an exemplary device 1400 comprising a substrate1410, a device 1401 disposed over the substrate 1410 having a devicefootprint, a barrier film 1406 disposed along the sides the footprint ofthe device 1401, and a top encapsulation comprising the barrier film1406, a glass layer 1411, and an epoxy 1412 (e.g. to couple the glasslayer 1411 to the barrier film layer 1406) disposed over the device1401. The barrier film 1406 can be used on top of the device 1401 toseparate the epoxy 1412 from the active device area (or a layer disposedthereon) of the device 1401. The epoxy seal 1411 can then be depositedover the barrier film 1406, followed by the glass encapsulation 1411.Finally, the barrier film 1406 may be deposited so to form the edge sealalong the sides of the footprint of device 1401, as shown in FIG. 14.

In some embodiments, a product may comprise a water vapor sensitiveelectronic component or layer (e.g. an electrode) that has an edgesealant barrier film deposited in a single chamber PE-CVD system usingan organosilicon precursor. The composition of the edge sealant barrierfilm may not change substantially when observed moving away from thedevice footprint of the device, parallel to the substrate, from theinner edge to the outer edge of the barrier film, along the entirethickness of the barrier film, including the interface of the barrierfilm with the substrate. In some embodiments, the length of theinterface of the barrier film with the substrate in a directionperpendicular to a side of the device footprint may be less than orequal to 3.0 mm. In some embodiments, the length of the interface of thebarrier film with the substrate in a direction perpendicular to a sideof the device footprint may be less than or equal to 2.0 mm. In someembodiments, the length of the interface of the barrier film with thesubstrate in a direction perpendicular to a side of the device footprintmay be less than or equal to 1.0 mm.

In some embodiments, a product may be provide that comprises a watervapor sensitive electronic component or layer (such as an electrode)with an edge sealant comprising a barrier film deposited in a singlechamber PE-CVD system using organosilicon precursor. The composition ofthe edge sealant barrier film may not change substantially when observedmoving away from the device footprint, parallel to the substrate, fromthe inner edge to the outer edge of the barrier film, along the entirethickness of the barrier film, including the interface of the barrierfilm with the substrate. The composition and density of the edge sealantbarrier film may be such that the ratio of the refractive index of theinterface region of the barrier film close the substrate (i.e. within 10nm) with that of the bulk of the barrier film is less than or equal to0.9993 but greater than or equal to 0.9247.

In some embodiments, a product may be provided that comprises a watervapor sensitive electronic component or layer (such as an electrode)with an edge sealant barrier film deposited in a single chamber PE-CVDsystem using organosilicon precursor. The composition of the edgesealant barrier film may not change substantially when observed movingaway from the device footprint of the device, parallel to the substrate,from the inner edge to the outer edge of the barrier film, along theentire thickness of the barrier film, including the interface of thebarrier with the substrate. The composition and density of the barrierfilm may be such that the refractive index of the interface region closeto the substrate (i.e. with in 10 nm) is more than 1.35 but less than1.459.

In some embodiments, the bulk diffusion coefficient of water vapor inthe barrier film may be less than 10⁻¹³ cm²/sec and the diffusioncoefficient of water vapor at the interface of the barrier film with thesubstrate may be less than or equal to 10⁻⁸, but greater than or equalto 10⁻¹³ cm²/sec when the external environment is at 65° C. and 85% RH.In some embodiments, the ratio of the bulk diffusion coefficient ofwater vapor in the barrier film compared to the diffusion coefficientalong the interface of the barrier film with the substrate may be lessthan or equal to 1.0 (i.e. they may be the same) but greater than orequal to 10⁻⁵. In some embodiments, the device may not show any edgeshrinkage of the active area for 1,000 hrs of storage at 65° C. and 85%RH.

In addition to the products described above, the inventors have alsofound methods of manufacturing such products. In this regard, in someembodiments, a first method may comprise the steps of providing asubstrate having a device disposed over the substrate having a devicefootprint, and fabricating a barrier film over the substrate andsubstantially along a side of the device footprint, where the barrierfilm may be fabricated so as to have a perpendicular length that is lessthan or equal to 3.0 mm (preferably less than 2.0 mm, and morepreferably less than 1.0 mm) from the side of the device footprint. Insome embodiments, the barrier film may comprise a mixture of a polymericmaterial and non-polymeric material.

The term “providing” is generally used in this context to be aninclusive term and encompass any manner of obtaining or making availablea substrate having a device disposed over the substrate for use in suchmethods. For instance, in some embodiments, the substrate and the device(and/or components thereof) may be acquired, such as by purchase from athird party. In some embodiments, the substrate and/or active area couldbe fabricated, manufactured, or otherwise assembled, or the componentscould be provided to a third party that may then fabricate or assemblethe substrate having a device disposed thereon.

Similarly, the term “fabricating” is also intended to be an inclusiveterm, and may comprise any suitable deposition process or othertechnique for disposing the barrier film over the substrate. This couldinclude, by way of example only, vacuum depositing a blanket layer ofbarrier film over the substrate and etching, cutting, or ablatingportions of the barrier film so that it has a perpendicular length thatis less than 3.0 mm; deposition of the barrier film through a mask suchthat it has a perpendicular length that is less than 3.0 mm, or anyother suitable method known in the art.

In some embodiments, in the first method as described above, the devicemay comprise an organic layer. In some embodiments, the organic layermay comprise an electroluminescent (EL) material. In some embodiments,the device may comprise an OLED. As noted above, although the inventorshave found that the use of a barrier film having a perpendicular lengththat is less than 3.0 mm (such as when the barrier film comprises amixture of a polymeric material and non-polymeric material) providebenefits to organic devices including increasing display and panel sizes(e.g. by decreasing border area (dead space)), embodiments are not solimited.

In some embodiments, in the first method as described above, the barrierfilm may be fabricated so as to have a perpendicular length that is lessthan or equal to 2.0 mm from the side of the device footprint. In someembodiments, the barrier film may be fabricated so as to have aperpendicular length that is less than or equal to 1.0 mm from the sideof the device footprint. As noted above, in general a smallerperpendicular length for the barrier film may allow for a smaller borderarea of the product, thereby reducing the size of the product orreducing the inefficient use of space. As was described above withreference to an exemplary product, in some embodiments, the barrier filmmay be fabricated or disposed so that it does not have any perpendicularlengths from the side of the device footprint that are greater than 3.0mm (preferably 2.0 mm, and more preferable greater than 1.0 mm).

In some embodiments, in the first method as described above, the step offabricating the barrier film may comprise chemical vapor deposition. Insome embodiments, the step of fabricating the barrier film may utilizean organosilicon precursor. However, as described above, the inventorshave found that a variety of precursors may be used to fabricate barrierfilms that have desired properties to form an edge seal, and may beselected based on the particular application or device that the barrierfilm is being applied thereto.

In some embodiments, in the first method as decried above, the step offabricating the barrier film so as to have a perpendicular length thatis less than or equal to 3.0 mm from a side of the device footprint maycomprise depositing the barrier film through a mask such that theperpendicular length is less than or equal to 3.0 mm from the side ofthe device footprint. The deposition may be performed in a vacuumprocess, such as CVD or PE-CVD.

In some embodiments, in the first method as described above, the step offabricating the barrier film so as to have a perpendicular length thatis less than or equal to 3.0 mm from the side of the device footprintmay comprise the steps of: depositing a barrier film over the substrateand substantially along a side of the device footprint, wherein thebarrier film is deposited so as to have a perpendicular length that isgreater than or equal to 3.0 mm from the side of the device footprint,and, after depositing the barrier film, breaking the barrier film suchthat the barrier film has a perpendicular length that is less than orequal to 3.0 mm from the side of the device footprint. In someembodiments, the step of breaking the barrier film may be accomplishedby, or in combination with, breaking the substrate. This exemplaryfabrication method may provide for increased efficiencies (particularlywhere the barrier film is also disposed over device) because the barrierfilm may be deposited as a blanket layer over the substrate (e.g. a maskneed not be precisely aligned for the deposition process). The substratemay be scribed (or ablated) at a predetermined location (e.g. within 3.0mm, preferably within 2.0 mm, and more preferably within 1.0 mm of theside of the device footprint) so as to be broken along the scribe. Whenthe substrate is broken, the size of the barrier film disposed on theportion of the substrate that the device footprint is also disposed onmay be reduced.

It should be appreciated that the various characteristics describedabove with reference to the components of the first product may applyequally to the components described with respect to the first method, aswould be understood by one of skill in the art. For example, the variousdescriptions of the composition of the barrier film, the fabrication ofother components (such as top sealant or encapsulation layers) etc., mayalso be performed in accordance with the first method.

In some embodiments, a first product prepared by a process may beprovided. The process for preparing the first product may comprise thesteps of providing a substrate having a device disposed over thesubstrate having a device footprint, and fabricating a barrier film overthe substrate and substantially along a side of the device footprint,where the barrier film may be fabricated so as to have a perpendicularlength that is less than or equal to 3.0 mm from the side of the devicefootprint. In some embodiments, the barrier film may comprise a mixtureof a polymeric material and non-polymeric material.

In some embodiments, in the first device prepared by a process asdescribed above, the device may comprise an organic layer. In someembodiments, the organic layer may comprise an organicelectroluminescent (EL) material. In some embodiments, the device may bean OLED.

In some embodiments, in the first product prepared by a process asdescribed above, the barrier film may be fabricated so as to haveperpendicular length that is less than or equal to 2.0 mm from the sideof the device footprint. In some embodiments, the barrier film may befabricated so as to have perpendicular length that is less than or equalto 1.0 mm from the side of the device footprint.

In some embodiments, in the first product prepared by a process asdescribed above, the step of fabricating the barrier film may comprisedepositing the first barrier film using an organosilicon precursor. Asnoted above, the inventors have found that the use of an organosiliconprecursor may provide a barrier film that has particular properties thatmay be well-suited for use as an edge seal, which properties may be finetuned based on the various deposition conditions and methods, asdescribed above and would be appreciated by a person of ordinary skillin the art after reading this disclosure. However, any suitableprecursor material may be utilized for some embodiments.

In some embodiments, the step of fabricating the barrier film maycomprise chemical vapor deposition. In some embodiments, the step offabricating the barrier film may comprise plasma enhance chemical vapordeposition (PE-CVD). In some embodiments, the barrier film consistsessentially of a mixture of polymeric silicon and inorganic silicon,where the weight ratio of polymeric silicon to inorganic silicon is inthe range of 95:5 to 5:95, and where the polymeric silicon and theinorganic silicon are created from the same precursor material. In someembodiments, at least an 0.1 μm thickness of the barrier film isdeposited under the same reaction conditions for all the reactionconditions in the deposition process and the water vapor transmissionrate is less than 10⁻⁶ g/m²/day through the at least 0.1 μm thickness ofthe barrier film.

In some embodiments, in the first product prepared by a process asdescribed above, where the step of fabricating the barrier filmcomprises depositing the first barrier film using an organosiliconprecursor, the precursor material may comprise hexamethyl disiloxane ordimethyl siloxane. In some embodiments, the precursor material maycomprise a single organosilicon compound. In some embodiments, theprecursor material may comprise a mixture of organosilicon compounds.

In some embodiments, in the first product prepared by a process asdescribed above, the step of fabricating the barrier film may comprisedepositing the barrier film through a mask such that the perpendicularlength is less than or equal to 3.0 mm from the side of the devicefootprint. In some embodiments, the perpendicular length may be lessthan or equal to 2.0 mm (and preferable less than 1.0 mm) from the sideof the device footprint.

It should be appreciated that the various characteristics describedabove with reference to the components of the first product and thefirst method may apply equally to the embodiments that comprise thefirst product prepared by a process, as would be understood by one ofskill in the art. This includes the various materials used, thestructures created, and the characteristics of the product and/or thebarrier film.

CONCLUSION

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

The above description is illustrative and is not restrictive. Manyvariations of the invention will become apparent to those skilled in theart upon review of the disclosure. The scope of the invention should,therefore, be determined not with reference to the above description,but instead should be determined with reference to the pending claimsalong with their full scope or equivalents.

Although many embodiments were described above as comprising differentfeatures and/or combination of features, a person of ordinary skill inthe art after reading this disclosure may understand that in someinstances, one or more of these components could be combined with any ofthe components or features described above. That is, one or morefeatures from any embodiment can be combined with one or more featuresof any other embodiment without departing from the scope of theinvention.

As noted previously, all measurements, dimensions, and materialsprovided herein within the specification or within the figures are byway of example only.

A recitation of “a,” “an,” or “the” is intended to mean “one or more”unless specifically indicated to the contrary. Reference to a “first”component does not necessarily require that a second component beprovided. Moreover reference to a “first” or a “second” component doesnot limit the referenced component to a particular location unlessexpressly stated.

All publications mentioned herein are incorporated herein by referenceto disclose and describe the methods and/or materials in connection withwhich the publications are cited. The publications discussed herein areprovided solely for their disclosure prior to the filing date of thepresent application. Nothing herein is to be construed as an admissionthat the present invention is not entitled to antedate such publicationby virtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates, which may need to beindependently confirmed.

The invention claimed is:
 1. A method comprising: providing a substratehaving a device disposed over the substrate, the device having a devicefootprint; fabricating a barrier layer over the device; and fabricatinga barrier film substantially along a side of the device footprint,wherein a footprint of the barrier film is not more than 3.0 mm widerthan the device footprint on one or more sides of the device.
 2. Themethod of claim 1, wherein the barrier layer comprises a mixture of anoxide and polymeric silicon.
 3. The method of claim 1, wherein thebarrier layer comprises at least 40% inorganic silicon.
 4. The method ofclaim 1, wherein the barrier layer is a multilayer barrier filmcomprising a polymeric layer and a non-polymeric layer.
 5. The method ofclaim 1, wherein the barrier layer comprises a mixture of polymericmaterial and non-polymeric material, and a weight ratio of polymeric tonon-polymeric material in the barrier layer is in a range of 25:75 to10:90.
 6. The method of claim 4, wherein the barrier layer has a wettingcontact angle in a range of 36° to 60°.
 7. The method of claim 1,wherein the barrier layer is a single-layer barrier film.
 8. The methodof claim 1, wherein the barrier film is a single-layer barrier film. 9.The method of claim 1, wherein the barrier layer is fabricated over thedevice prior to fabricating the barrier film along the side of thedevice footprint.
 10. The method of claim 9, wherein the step offabricating the barrier film comprises fabricating the barrier film overat least a portion of the barrier layer.
 11. The method of claim 1,wherein the step of fabricating the barrier layer comprises: depositingan epoxy layer directly over the device; and depositing a glassencapsulation layer directly over the epoxy layer such that the glassencapsulation layer is coupled to the epoxy layer.
 12. The method ofclaim 1, wherein the step of fabricating the barrier layer comprises:depositing a hybrid polymeric/non-polymeric material barrier layerdirectly over the device; depositing an epoxy layer directly over thehybrid layer; and depositing a glass encapsulation layer directly on theepoxy layer such that the glass encapsulation layer is coupled to theepoxy layer.
 13. The method of claim 1, wherein the barrier layercomprises a plurality of inorganic layers and a plurality of polymerlayers.
 14. The method of claim 13, further comprising depositingalternating layers of the inorganic layers and the polymer layers. 15.The method of claim 13, wherein the plurality of inorganic layers andthe plurality of polymer layers are deposited through a single mask.